Original patch by rlarocque@chromium.org at http://codereview.chromium.org/7633077/

Fragment syncapi.h into sync/internal_api/*

This commit splits syncapi.cc and syncapi.h into many files. Most of these files have been moved to the newly created chrome/browser/sync/internal_api.

Each of the following classes now have their own .cc and .h files:
- BaseNode
- ReadNode
- WriteNode
- BaseTransaction
- ReadTransaction
- WriteTransaction
- UserShare
- SyncManager

Functions formerly declared at file-scope in syncapi.cc and shared among several classes are now declared in engine/syncapi_internal.h. We intend to use DEPS rules to prevent these functions from being included in non-syncapi classes.

Test classes closely related to syncapi.h classes have been moved from engine to internal_api.

This change necessarily touches the #include lists for lots of files and some of the sources lists in .gyp.

This change should have no effect on program behaviour.

BUG=19878
TEST=

Review URL: http://codereview.chromium.org/7624009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@97238 0039d316-1c4b-4281-b951-d872f2087c98

99 files changed, 2721 insertions, 2296 deletions

diff --git a/chrome/browser/sync/abstract_profile_sync_service_test.cc b/chrome/browser/sync/abstract_profile_sync_service_test.cc
index 2dcace3..640b273 100644
--- a/chrome/browser/sync/abstract_profile_sync_service_test.cc
+++ b/chrome/browser/sync/abstract_profile_sync_service_test.cc
@@ -5,7 +5,7 @@
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
 
 #include "base/tracked.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/protocol/sync.pb.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/browser/sync/syncable/syncable.h"
diff --git a/chrome/browser/sync/engine/DEPS b/chrome/browser/sync/engine/DEPS
index ce9fd8a..0142088 100644
--- a/chrome/browser/sync/engine/DEPS
+++ b/chrome/browser/sync/engine/DEPS
@@ -11,13 +11,13 @@ include_rules = [
   "+chrome/browser/sync/syncable",
   "+chrome/browser/sync/util",
 
+  # TODO(rlarocque) 19878: Move remaining syncapi-related headers to
+  # internal_api/, then remove this DEPS rule.
+  "+chrome/browser/sync/internal_api",
+
   # this should live in base
   "+chrome/browser/sync/weak_handle.h",
 
-  # unittests need this for mac osx keychain overriding
-  "+chrome/browser/password_manager/encryptor.h",
-
-  "+chrome/common/net/gaia/google_service_auth_error.h",
   "+chrome/common/net/http_return.h",
 
   # various command line flags
diff --git a/chrome/browser/sync/engine/all_status.h b/chrome/browser/sync/engine/all_status.h
index dd1461b..bef60c9 100644
--- a/chrome/browser/sync/engine/all_status.h
+++ b/chrome/browser/sync/engine/all_status.h
@@ -13,8 +13,8 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/engine/syncer_types.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 
 namespace browser_sync {
diff --git a/chrome/browser/sync/engine/change_reorder_buffer.cc b/chrome/browser/sync/engine/change_reorder_buffer.cc
index 76f6e03..189c072 100644
--- a/chrome/browser/sync/engine/change_reorder_buffer.cc
+++ b/chrome/browser/sync/engine/change_reorder_buffer.cc
@@ -10,6 +10,7 @@
 #include <utility>  // for pair<>
 #include <vector>
 
+#include "chrome/browser/sync/internal_api/read_node.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 #include "chrome/browser/sync/syncable/syncable.h"
 
diff --git a/chrome/browser/sync/engine/change_reorder_buffer.h b/chrome/browser/sync/engine/change_reorder_buffer.h
index f4062ef..25bb086 100644
--- a/chrome/browser/sync/engine/change_reorder_buffer.h
+++ b/chrome/browser/sync/engine/change_reorder_buffer.h
@@ -14,7 +14,8 @@
 #include <vector>
 
 #include "base/memory/linked_ptr.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/protocol/sync.pb.h"
 
 namespace sync_api {
diff --git a/chrome/browser/sync/engine/net/server_connection_manager.cc b/chrome/browser/sync/engine/net/server_connection_manager.cc
index 2765508..3604026 100644
--- a/chrome/browser/sync/engine/net/server_connection_manager.cc
+++ b/chrome/browser/sync/engine/net/server_connection_manager.cc
@@ -13,7 +13,6 @@
 #include "base/command_line.h"
 #include "build/build_config.h"
 #include "chrome/browser/sync/engine/net/url_translator.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/engine/syncer.h"
 #include "chrome/browser/sync/engine/syncproto.h"
 #include "chrome/browser/sync/protocol/sync.pb.h"
diff --git a/chrome/browser/sync/engine/net/syncapi_server_connection_manager.cc b/chrome/browser/sync/engine/net/syncapi_server_connection_manager.cc
index b05c525..826f930 100644
--- a/chrome/browser/sync/engine/net/syncapi_server_connection_manager.cc
+++ b/chrome/browser/sync/engine/net/syncapi_server_connection_manager.cc
@@ -6,7 +6,6 @@
 
 #include "chrome/browser/sync/engine/http_post_provider_factory.h"
 #include "chrome/browser/sync/engine/http_post_provider_interface.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/util/oauth.h"
 #include "chrome/common/net/http_return.h"
 
diff --git a/chrome/browser/sync/engine/nigori_util.cc b/chrome/browser/sync/engine/nigori_util.cc
index b305c49..ce721c2 100644
--- a/chrome/browser/sync/engine/nigori_util.cc
+++ b/chrome/browser/sync/engine/nigori_util.cc
@@ -8,8 +8,8 @@
 #include <string>
 #include <vector>
 
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/engine/syncer_util.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
 #include "chrome/browser/sync/syncable/syncable.h"
 #include "chrome/browser/sync/util/cryptographer.h"
 
diff --git a/chrome/browser/sync/engine/sync_scheduler.h b/chrome/browser/sync/engine/sync_scheduler.h
index eda53b1..7a025fb 100644
--- a/chrome/browser/sync/engine/sync_scheduler.h
+++ b/chrome/browser/sync/engine/sync_scheduler.h
@@ -19,14 +19,13 @@
 #include "base/time.h"
 #include "base/timer.h"
 #include "chrome/browser/sync/engine/configure_reason.h"
+#include "chrome/browser/sync/engine/net/server_connection_manager.h"
 #include "chrome/browser/sync/engine/nudge_source.h"
 #include "chrome/browser/sync/engine/polling_constants.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/engine/syncer.h"
-#include "chrome/browser/sync/syncable/model_type_payload_map.h"
-#include "chrome/browser/sync/engine/net/server_connection_manager.h"
-#include "chrome/browser/sync/sessions/sync_session.h"
 #include "chrome/browser/sync/sessions/sync_session_context.h"
+#include "chrome/browser/sync/sessions/sync_session.h"
+#include "chrome/browser/sync/syncable/model_type_payload_map.h"
 
 class MessageLoop;
 
diff --git a/chrome/browser/sync/engine/syncapi.h b/chrome/browser/sync/engine/syncapi.h
deleted file mode 100644
index eaf9a56..0000000
--- a/chrome/browser/sync/engine/syncapi.h
+++ /dev/null
@@ -1,1095 +0,0 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// This file defines the "sync API", an interface to the syncer
-// backend that exposes (1) the core functionality of maintaining a consistent
-// local snapshot of a hierarchical object set; (2) a means to transactionally
-// access and modify those objects; (3) a means to control client/server
-// synchronization tasks, namely: pushing local object modifications to a
-// server, pulling nonlocal object modifications from a server to this client,
-// and resolving conflicts that may arise between the two; and (4) an
-// abstraction of some external functionality that is to be provided by the
-// host environment.
-//
-// This interface is used as the entry point into the syncer backend
-// when the backend is compiled as a library and embedded in another
-// application.  A goal for this interface layer is to depend on very few
-// external types, so that an application can use the sync backend
-// without introducing a dependency on specific types.  A non-goal is to
-// have binary compatibility across versions or compilers; this allows the
-// interface to use C++ classes.  An application wishing to use the sync API
-// should ideally compile the syncer backend and this API as part of the
-// application's own build, to avoid e.g. mismatches in calling convention,
-// structure padding, or name mangling that could arise if there were a
-// compiler mismatch.
-//
-// The schema of the objects in the sync domain is based on the model, which
-// is essentially a hierarchy of items and folders similar to a filesystem,
-// but with a few important differences.  The sync API contains fields
-// such as URL to easily allow the embedding application to store web
-// browser bookmarks.  Also, the sync API allows duplicate titles in a parent.
-// Consequently, it does not support looking up an object by title
-// and parent, since such a lookup is not uniquely determined.  Lastly,
-// unlike a filesystem model, objects in the Sync API model have a strict
-// ordering within a parent; the position is manipulable by callers, and
-// children of a node can be enumerated in the order of their position.
-
-#ifndef CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_H_
-#define CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_H_
-#pragma once
-
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/callback_old.h"
-#include "base/gtest_prod_util.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/tracked.h"
-#include "build/build_config.h"
-#include "chrome/browser/sync/engine/configure_reason.h"
-#include "chrome/browser/sync/protocol/password_specifics.pb.h"
-#include "chrome/browser/sync/syncable/model_type.h"
-#include "chrome/browser/sync/util/cryptographer.h"
-#include "chrome/browser/sync/weak_handle.h"
-#include "chrome/common/net/gaia/google_service_auth_error.h"
-#include "googleurl/src/gurl.h"
-
-class FilePath;
-
-namespace base {
-class DictionaryValue;
-}
-
-namespace browser_sync {
-class JsBackend;
-class JsEventHandler;
-class ModelSafeWorkerRegistrar;
-
-namespace sessions {
-struct SyncSessionSnapshot;
-}
-}
-
-namespace sync_notifier {
-class SyncNotifier;
-}  // namespace sync_notifier
-
-// Forward declarations of internal class types so that sync API objects
-// may have opaque pointers to these types.
-namespace syncable {
-class BaseTransaction;
-class DirectoryManager;
-class Entry;
-class MutableEntry;
-class ReadTransaction;
-class ScopedDirLookup;
-class WriteTransaction;
-}
-
-namespace sync_pb {
-class AppSpecifics;
-class AutofillSpecifics;
-class AutofillProfileSpecifics;
-class BookmarkSpecifics;
-class EntitySpecifics;
-class ExtensionSpecifics;
-class SessionSpecifics;
-class NigoriSpecifics;
-class PasswordSpecifics;
-class PreferenceSpecifics;
-class PasswordSpecifics;
-class PasswordSpecificsData;
-class ThemeSpecifics;
-class TypedUrlSpecifics;
-}
-
-namespace tracked_objects {
-class Location;
-}  // namespace tracked_objects
-
-namespace sync_api {
-
-class BaseTransaction;
-class HttpPostProviderFactory;
-class SyncManager;
-class WriteTransaction;
-
-syncable::ModelTypeSet GetEncryptedTypes(
-    const sync_api::BaseTransaction* trans);
-
-
-// Reasons due to which browser_sync::Cryptographer might require a passphrase.
-enum PassphraseRequiredReason {
-  REASON_PASSPHRASE_NOT_REQUIRED = 0,  // Initial value.
-  REASON_ENCRYPTION = 1,               // The cryptographer requires a
-                                       // passphrase for its first attempt at
-                                       // encryption. Happens only during
-                                       // migration or upgrade.
-  REASON_DECRYPTION = 2,               // The cryptographer requires a
-                                       // passphrase for its first attempt at
-                                       // decryption.
-  REASON_SET_PASSPHRASE_FAILED = 3,    // The cryptographer requires a new
-                                       // passphrase because its attempt at
-                                       // decryption with the cached passphrase
-                                       // was unsuccessful.
-};
-
-// Returns the string representation of a PassphraseRequiredReason value.
-std::string PassphraseRequiredReasonToString(PassphraseRequiredReason reason);
-
-// A UserShare encapsulates the syncable pieces that represent an authenticated
-// user and their data (share).
-// This encompasses all pieces required to build transaction objects on the
-// syncable share.
-struct UserShare {
-  UserShare();
-  ~UserShare();
-
-  // The DirectoryManager itself, which is the parent of Transactions and can
-  // be shared across multiple threads (unlike Directory).
-  scoped_ptr<syncable::DirectoryManager> dir_manager;
-
-  // The username of the sync user.
-  std::string name;
-};
-
-bool InitialSyncEndedForTypes(syncable::ModelTypeSet types, UserShare* share);
-
-// Contains everything needed to talk to and identify a user account.
-struct SyncCredentials {
-  std::string email;
-  std::string sync_token;
-};
-
-// A valid BaseNode will never have an ID of zero.
-static const int64 kInvalidId = 0;
-
-// BaseNode wraps syncable::Entry, and corresponds to a single object's state.
-// This, like syncable::Entry, is intended for use on the stack.  A valid
-// transaction is necessary to create a BaseNode or any of its children.
-// Unlike syncable::Entry, a sync API BaseNode is identified primarily by its
-// int64 metahandle, which we call an ID here.
-class BaseNode {
- public:
-  // All subclasses of BaseNode must provide a way to initialize themselves by
-  // doing an ID lookup.  Returns false on failure.  An invalid or deleted
-  // ID will result in failure.
-  virtual bool InitByIdLookup(int64 id) = 0;
-
-  // All subclasses of BaseNode must also provide a way to initialize themselves
-  // by doing a client tag lookup. Returns false on failure. A deleted node
-  // will return FALSE.
-  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
-      const std::string& tag) = 0;
-
-  // Each object is identified by a 64-bit id (internally, the syncable
-  // metahandle).  These ids are strictly local handles.  They will persist
-  // on this client, but the same object on a different client may have a
-  // different ID value.
-  virtual int64 GetId() const;
-
-  // Returns the modification time of the object (in TimeTicks internal format).
-  int64 GetModificationTime() const;
-
-  // Nodes are hierarchically arranged into a single-rooted tree.
-  // InitByRootLookup on ReadNode allows access to the root. GetParentId is
-  // how you find a node's parent.
-  int64 GetParentId() const;
-
-  // Nodes are either folders or not.  This corresponds to the IS_DIR property
-  // of syncable::Entry.
-  bool GetIsFolder() const;
-
-  // Returns the title of the object.
-  // Uniqueness of the title is not enforced on siblings -- it is not an error
-  // for two children to share a title.
-  std::string GetTitle() const;
-
-  // Returns the model type of this object.  The model type is set at node
-  // creation time and is expected never to change.
-  syncable::ModelType GetModelType() const;
-
-  // Getter specific to the BOOKMARK datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == BOOKMARK.
-  const sync_pb::BookmarkSpecifics& GetBookmarkSpecifics() const;
-
-  // Legacy, bookmark-specific getter that wraps GetBookmarkSpecifics() above.
-  // Returns the URL of a bookmark object.
-  // TODO(ncarter): Remove this datatype-specific accessor.
-  GURL GetURL() const;
-
-  // Legacy, bookmark-specific getter that wraps GetBookmarkSpecifics() above.
-  // Fill in a vector with the byte data of this node's favicon.  Assumes
-  // that the node is a bookmark.
-  // Favicons are expected to be PNG images, and though no verification is
-  // done on the syncapi client of this, the server may reject favicon updates
-  // that are invalid for whatever reason.
-  // TODO(ncarter): Remove this datatype-specific accessor.
-  void GetFaviconBytes(std::vector<unsigned char>* output) const;
-
-  // Getter specific to the APPS datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == APPS.
-  const sync_pb::AppSpecifics& GetAppSpecifics() const;
-
-  // Getter specific to the AUTOFILL datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == AUTOFILL.
-  const sync_pb::AutofillSpecifics& GetAutofillSpecifics() const;
-
-  virtual const sync_pb::AutofillProfileSpecifics&
-      GetAutofillProfileSpecifics() const;
-
-  // Getter specific to the NIGORI datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == NIGORI.
-  const sync_pb::NigoriSpecifics& GetNigoriSpecifics() const;
-
-  // Getter specific to the PASSWORD datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == PASSWORD.
-  const sync_pb::PasswordSpecificsData& GetPasswordSpecifics() const;
-
-  // Getter specific to the PREFERENCE datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == PREFERENCE.
-  const sync_pb::PreferenceSpecifics& GetPreferenceSpecifics() const;
-
-  // Getter specific to the THEME datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == THEME.
-  const sync_pb::ThemeSpecifics& GetThemeSpecifics() const;
-
-  // Getter specific to the TYPED_URLS datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == TYPED_URLS.
-  const sync_pb::TypedUrlSpecifics& GetTypedUrlSpecifics() const;
-
-  // Getter specific to the EXTENSIONS datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == EXTENSIONS.
-  const sync_pb::ExtensionSpecifics& GetExtensionSpecifics() const;
-
-  // Getter specific to the SESSIONS datatype.  Returns protobuf
-  // data.  Can only be called if GetModelType() == SESSIONS.
-  const sync_pb::SessionSpecifics& GetSessionSpecifics() const;
-
-  const sync_pb::EntitySpecifics& GetEntitySpecifics() const;
-
-  // Returns the local external ID associated with the node.
-  int64 GetExternalId() const;
-
-  // Return the ID of the node immediately before this in the sibling order.
-  // For the first node in the ordering, return 0.
-  int64 GetPredecessorId() const;
-
-  // Return the ID of the node immediately after this in the sibling order.
-  // For the last node in the ordering, return 0.
-  virtual int64 GetSuccessorId() const;
-
-  // Return the ID of the first child of this node.  If this node has no
-  // children, return 0.
-  virtual int64 GetFirstChildId() const;
-
-  // These virtual accessors provide access to data members of derived classes.
-  virtual const syncable::Entry* GetEntry() const = 0;
-  virtual const BaseTransaction* GetTransaction() const = 0;
-
-  // Dumps a summary of node info into a DictionaryValue and returns it.
-  // Transfers ownership of the DictionaryValue to the caller.
-  base::DictionaryValue* GetSummaryAsValue() const;
-
-  // Dumps all node details into a DictionaryValue and returns it.
-  // Transfers ownership of the DictionaryValue to the caller.
-  base::DictionaryValue* GetDetailsAsValue() const;
-
- protected:
-  BaseNode();
-  virtual ~BaseNode();
-  // The server has a size limit on client tags, so we generate a fixed length
-  // hash locally. This also ensures that ModelTypes have unique namespaces.
-  static std::string GenerateSyncableHash(syncable::ModelType model_type,
-      const std::string& client_tag);
-
-  // Determines whether part of the entry is encrypted, and if so attempts to
-  // decrypt it. Unless decryption is necessary and fails, this will always
-  // return |true|. If the contents are encrypted, the decrypted data will be
-  // stored in |unencrypted_data_|.
-  // This method is invoked once when the BaseNode is initialized.
-  bool DecryptIfNecessary();
-
-  // Returns the unencrypted specifics associated with |entry|. If |entry| was
-  // not encrypted, it directly returns |entry|'s EntitySpecifics. Otherwise,
-  // returns |unencrypted_data_|.
-  const sync_pb::EntitySpecifics& GetUnencryptedSpecifics(
-      const syncable::Entry* entry) const;
-
-  // Copy |specifics| into |unencrypted_data_|.
-  void SetUnencryptedSpecifics(const sync_pb::EntitySpecifics& specifics);
-
- private:
-  void* operator new(size_t size);  // Node is meant for stack use only.
-
-  // A holder for the unencrypted data stored in an encrypted node.
-  sync_pb::EntitySpecifics unencrypted_data_;
-
-  // Same as |unencrypted_data_|, but for legacy password encryption.
-  scoped_ptr<sync_pb::PasswordSpecificsData> password_data_;
-
-  friend class SyncApiTest;
-  FRIEND_TEST_ALL_PREFIXES(SyncApiTest, GenerateSyncableHash);
-
-  DISALLOW_COPY_AND_ASSIGN(BaseNode);
-};
-
-// WriteNode extends BaseNode to add mutation, and wraps
-// syncable::MutableEntry. A WriteTransaction is needed to create a WriteNode.
-class WriteNode : public BaseNode {
- public:
-  // Create a WriteNode using the given transaction.
-  explicit WriteNode(WriteTransaction* transaction);
-  virtual ~WriteNode();
-
-  // A client must use one (and only one) of the following Init variants to
-  // populate the node.
-
-  // BaseNode implementation.
-  virtual bool InitByIdLookup(int64 id);
-  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
-      const std::string& tag);
-
-  // Create a new node with the specified parent and predecessor.  |model_type|
-  // dictates the type of the item, and controls which EntitySpecifics proto
-  // extension can be used with this item.  Use a NULL |predecessor|
-  // to indicate that this is to be the first child.
-  // |predecessor| must be a child of |new_parent| or NULL. Returns false on
-  // failure.
-  bool InitByCreation(syncable::ModelType model_type,
-                      const BaseNode& parent,
-                      const BaseNode* predecessor);
-
-  // Create nodes using this function if they're unique items that
-  // you want to fetch using client_tag. Note that the behavior of these
-  // items is slightly different than that of normal items.
-  // Most importantly, if it exists locally, this function will
-  // actually undelete it
-  // Client unique tagged nodes must NOT be folders.
-  bool InitUniqueByCreation(syncable::ModelType model_type,
-                            const BaseNode& parent,
-                            const std::string& client_tag);
-
-  // Each server-created permanent node is tagged with a unique string.
-  // Look up the node with the particular tag.  If it does not exist,
-  // return false.
-  bool InitByTagLookup(const std::string& tag);
-
-  // These Set() functions correspond to the Get() functions of BaseNode.
-  void SetIsFolder(bool folder);
-  void SetTitle(const std::wstring& title);
-
-  // External ID is a client-only field, so setting it doesn't cause the item to
-  // be synced again.
-  void SetExternalId(int64 external_id);
-
-  // Remove this node and its children.
-  void Remove();
-
-  // Set a new parent and position.  Position is specified by |predecessor|; if
-  // it is NULL, the node is moved to the first position.  |predecessor| must
-  // be a child of |new_parent| or NULL.  Returns false on failure..
-  bool SetPosition(const BaseNode& new_parent, const BaseNode* predecessor);
-
-  // Set the bookmark specifics (url and favicon).
-  // Should only be called if GetModelType() == BOOKMARK.
-  void SetBookmarkSpecifics(const sync_pb::BookmarkSpecifics& specifics);
-
-  // Legacy, bookmark-specific setters that wrap SetBookmarkSpecifics() above.
-  // Should only be called if GetModelType() == BOOKMARK.
-  // TODO(ncarter): Remove these two datatype-specific accessors.
-  void SetURL(const GURL& url);
-  void SetFaviconBytes(const std::vector<unsigned char>& bytes);
-
-  // Generic set specifics method. Will extract the model type from |specifics|.
-  void SetEntitySpecifics(const sync_pb::EntitySpecifics& specifics);
-
-  // Resets the EntitySpecifics for this node based on the unencrypted data.
-  // Will encrypt if necessary.
-  void ResetFromSpecifics();
-
-  // TODO(sync): Remove the setters below when the corresponding data
-  // types are ported to the new sync service API.
-
-  // Set the app specifics (id, update url, enabled state, etc).
-  // Should only be called if GetModelType() == APPS.
-  void SetAppSpecifics(const sync_pb::AppSpecifics& specifics);
-
-  // Set the autofill specifics (name and value).
-  // Should only be called if GetModelType() == AUTOFILL.
-  void SetAutofillSpecifics(const sync_pb::AutofillSpecifics& specifics);
-
-  void SetAutofillProfileSpecifics(
-      const sync_pb::AutofillProfileSpecifics& specifics);
-
-  // Set the nigori specifics.
-  // Should only be called if GetModelType() == NIGORI.
-  void SetNigoriSpecifics(const sync_pb::NigoriSpecifics& specifics);
-
-  // Set the password specifics.
-  // Should only be called if GetModelType() == PASSWORD.
-  void SetPasswordSpecifics(const sync_pb::PasswordSpecificsData& specifics);
-
-  // Set the theme specifics (name and value).
-  // Should only be called if GetModelType() == THEME.
-  void SetThemeSpecifics(const sync_pb::ThemeSpecifics& specifics);
-
-  // Set the typed_url specifics (url, title, typed_count, etc).
-  // Should only be called if GetModelType() == TYPED_URLS.
-  void SetTypedUrlSpecifics(const sync_pb::TypedUrlSpecifics& specifics);
-
-  // Set the extension specifics (id, update url, enabled state, etc).
-  // Should only be called if GetModelType() == EXTENSIONS.
-  void SetExtensionSpecifics(const sync_pb::ExtensionSpecifics& specifics);
-
-  // Set the session specifics (windows, tabs, navigations etc.).
-  // Should only be called if GetModelType() == SESSIONS.
-  void SetSessionSpecifics(const sync_pb::SessionSpecifics& specifics);
-
-  // Stores |new_specifics| into |entry|, encrypting if necessary.
-  // Returns false if an error encrypting occurred (does not modify |entry|).
-  // Note: gracefully handles new_specifics aliasing with entry->Get(SPECIFICS).
-  static bool UpdateEntryWithEncryption(
-      browser_sync::Cryptographer* cryptographer,
-      const sync_pb::EntitySpecifics& new_specifics,
-      syncable::MutableEntry* entry);
-
-  // Implementation of BaseNode's abstract virtual accessors.
-  virtual const syncable::Entry* GetEntry() const;
-
-  virtual const BaseTransaction* GetTransaction() const;
-
- private:
-  void* operator new(size_t size);  // Node is meant for stack use only.
-
-  // Helper to set model type. This will clear any specifics data.
-  void PutModelType(syncable::ModelType model_type);
-
-  // Helper to set the previous node.
-  void PutPredecessor(const BaseNode* predecessor);
-
-  // Sets IS_UNSYNCED and SYNCING to ensure this entry is considered in an
-  // upcoming commit pass.
-  void MarkForSyncing();
-
-  // The underlying syncable object which this class wraps.
-  syncable::MutableEntry* entry_;
-
-  // The sync API transaction that is the parent of this node.
-  WriteTransaction* transaction_;
-
-  DISALLOW_COPY_AND_ASSIGN(WriteNode);
-};
-
-// ReadNode wraps a syncable::Entry to provide the functionality of a
-// read-only BaseNode.
-class ReadNode : public BaseNode {
- public:
-  // Create an unpopulated ReadNode on the given transaction.  Call some flavor
-  // of Init to populate the ReadNode with a database entry.
-  explicit ReadNode(const BaseTransaction* transaction);
-  virtual ~ReadNode();
-
-  // A client must use one (and only one) of the following Init variants to
-  // populate the node.
-
-  // BaseNode implementation.
-  virtual bool InitByIdLookup(int64 id);
-  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
-      const std::string& tag);
-
-  // There is always a root node, so this can't fail.  The root node is
-  // never mutable, so root lookup is only possible on a ReadNode.
-  void InitByRootLookup();
-
-  // Each server-created permanent node is tagged with a unique string.
-  // Look up the node with the particular tag.  If it does not exist,
-  // return false.
-  bool InitByTagLookup(const std::string& tag);
-
-  // Implementation of BaseNode's abstract virtual accessors.
-  virtual const syncable::Entry* GetEntry() const;
-  virtual const BaseTransaction* GetTransaction() const;
-
- protected:
-  ReadNode();
-
- private:
-  void* operator new(size_t size);  // Node is meant for stack use only.
-
-  // The underlying syncable object which this class wraps.
-  syncable::Entry* entry_;
-
-  // The sync API transaction that is the parent of this node.
-  const BaseTransaction* transaction_;
-
-  DISALLOW_COPY_AND_ASSIGN(ReadNode);
-};
-
-// Sync API's BaseTransaction, ReadTransaction, and WriteTransaction allow for
-// batching of several read and/or write operations.  The read and write
-// operations are performed by creating ReadNode and WriteNode instances using
-// the transaction. These transaction classes wrap identically named classes in
-// syncable, and are used in a similar way. Unlike syncable::BaseTransaction,
-// whose construction requires an explicit syncable::ScopedDirLookup, a sync
-// API BaseTransaction creates its own ScopedDirLookup implicitly.
-class BaseTransaction {
- public:
-  // Provide access to the underlying syncable.h objects from BaseNode.
-  virtual syncable::BaseTransaction* GetWrappedTrans() const = 0;
-  const syncable::ScopedDirLookup& GetLookup() const { return *lookup_; }
-  browser_sync::Cryptographer* GetCryptographer() const {
-    return cryptographer_;
-  }
-
- protected:
-  // The ScopedDirLookup is created in the constructor and destroyed
-  // in the destructor.  Creation of the ScopedDirLookup is not expected
-  // to fail.
-  explicit BaseTransaction(UserShare* share);
-  virtual ~BaseTransaction();
-
-  BaseTransaction() { lookup_= NULL; }
-
- private:
-  // A syncable ScopedDirLookup, which is the parent of syncable transactions.
-  syncable::ScopedDirLookup* lookup_;
-
-  browser_sync::Cryptographer* cryptographer_;
-
-  DISALLOW_COPY_AND_ASSIGN(BaseTransaction);
-};
-
-// TODO(akalin): Make ReadTransaction/WriteTransaction take a Location
-// parameter.
-
-// Sync API's ReadTransaction is a read-only BaseTransaction.  It wraps
-// a syncable::ReadTransaction.
-class ReadTransaction : public BaseTransaction {
- public:
-  // Start a new read-only transaction on the specified repository.
-  ReadTransaction(const tracked_objects::Location& from_here,
-                  UserShare* share);
-
-  // Resume the middle of a transaction. Will not close transaction.
-  ReadTransaction(UserShare* share, syncable::BaseTransaction* trans);
-
-  virtual ~ReadTransaction();
-
-  // BaseTransaction override.
-  virtual syncable::BaseTransaction* GetWrappedTrans() const;
- private:
-  void* operator new(size_t size);  // Transaction is meant for stack use only.
-
-  // The underlying syncable object which this class wraps.
-  syncable::BaseTransaction* transaction_;
-  bool close_transaction_;
-
-  DISALLOW_COPY_AND_ASSIGN(ReadTransaction);
-};
-
-// Sync API's WriteTransaction is a read/write BaseTransaction.  It wraps
-// a syncable::WriteTransaction.
-//
-// NOTE: Only a single model type can be mutated for a given
-// WriteTransaction.
-class WriteTransaction : public BaseTransaction {
- public:
-  // Start a new read/write transaction.
-  WriteTransaction(const tracked_objects::Location& from_here,
-                   UserShare* share);
-  virtual ~WriteTransaction();
-
-  // Provide access to the syncable.h transaction from the API WriteNode.
-  virtual syncable::BaseTransaction* GetWrappedTrans() const;
-  syncable::WriteTransaction* GetWrappedWriteTrans() { return transaction_; }
-
- protected:
-  WriteTransaction() {}
-
-  void SetTransaction(syncable::WriteTransaction* trans) {
-      transaction_ = trans;
-  }
-
- private:
-  void* operator new(size_t size);  // Transaction is meant for stack use only.
-
-  // The underlying syncable object which this class wraps.
-  syncable::WriteTransaction* transaction_;
-
-  DISALLOW_COPY_AND_ASSIGN(WriteTransaction);
-};
-
-// SyncManager encapsulates syncable::DirectoryManager and serves as the parent
-// of all other objects in the sync API.  SyncManager is thread-safe.  If
-// multiple threads interact with the same local sync repository (i.e. the
-// same sqlite database), they should share a single SyncManager instance.  The
-// caller should typically create one SyncManager for the lifetime of a user
-// session.
-class SyncManager {
- public:
-  // SyncInternal contains the implementation of SyncManager, while abstracting
-  // internal types from clients of the interface.
-  class SyncInternal;
-
-  // TODO(zea): One day get passwords playing nicely with the rest of encryption
-  // and get rid of this.
-  class ExtraPasswordChangeRecordData {
-   public:
-    ExtraPasswordChangeRecordData();
-    explicit ExtraPasswordChangeRecordData(
-        const sync_pb::PasswordSpecificsData& data);
-    virtual ~ExtraPasswordChangeRecordData();
-
-    // Transfers ownership of the DictionaryValue to the caller.
-    virtual base::DictionaryValue* ToValue() const;
-
-    const sync_pb::PasswordSpecificsData& unencrypted() const;
-   private:
-    sync_pb::PasswordSpecificsData unencrypted_;
-  };
-
-  // ChangeRecord indicates a single item that changed as a result of a sync
-  // operation.  This gives the sync id of the node that changed, and the type
-  // of change.  To get the actual property values after an ADD or UPDATE, the
-  // client should get the node with InitByIdLookup(), using the provided id.
-  struct ChangeRecord {
-    enum Action {
-      ACTION_ADD,
-      ACTION_DELETE,
-      ACTION_UPDATE,
-    };
-    ChangeRecord();
-    ~ChangeRecord();
-
-    // Transfers ownership of the DictionaryValue to the caller.
-    base::DictionaryValue* ToValue(const BaseTransaction* trans) const;
-
-    int64 id;
-    Action action;
-    sync_pb::EntitySpecifics specifics;
-    linked_ptr<ExtraPasswordChangeRecordData> extra;
-  };
-
-  // Status encapsulates detailed state about the internals of the SyncManager.
-  struct Status {
-    // Summary is a distilled set of important information that the end-user may
-    // wish to be informed about (through UI, for example). Note that if a
-    // summary state requires user interaction (such as auth failures), more
-    // detailed information may be contained in additional status fields.
-    enum Summary {
-      // The internal instance is in an unrecognizable state. This should not
-      // happen.
-      INVALID = 0,
-      // Can't connect to server, but there are no pending changes in
-      // our local cache.
-      OFFLINE,
-      // Can't connect to server, and there are pending changes in our
-      // local cache.
-      OFFLINE_UNSYNCED,
-      // Connected and syncing.
-      SYNCING,
-      // Connected, no pending changes.
-      READY,
-      // Internal sync error.
-      CONFLICT,
-      // Can't connect to server, and we haven't completed the initial
-      // sync yet.  So there's nothing we can do but wait for the server.
-      OFFLINE_UNUSABLE,
-
-      SUMMARY_STATUS_COUNT,
-    };
-
-    Status();
-    ~Status();
-
-    Summary summary;
-    bool authenticated;      // Successfully authenticated via GAIA.
-    bool server_up;          // True if we have received at least one good
-                             // reply from the server.
-    bool server_reachable;   // True if we received any reply from the server.
-    bool server_broken;      // True of the syncer is stopped because of server
-                             // issues.
-    bool notifications_enabled;  // True only if subscribed for notifications.
-
-    // Notifications counters updated by the actions in synapi.
-    int notifications_received;
-    int notifiable_commits;
-
-    // The max number of consecutive errors from any component.
-    int max_consecutive_errors;
-
-    int unsynced_count;
-
-    int conflicting_count;
-    bool syncing;
-    // True after a client has done a first sync.
-    bool initial_sync_ended;
-    // True if any syncer is stuck.
-    bool syncer_stuck;
-
-    // Total updates available.  If zero, nothing left to download.
-    int64 updates_available;
-    // Total updates received by the syncer since browser start.
-    int updates_received;
-
-    // Of updates_received, how many were tombstones.
-    int tombstone_updates_received;
-    bool disk_full;
-
-    // Total number of overwrites due to conflict resolver since browser start.
-    int num_local_overwrites_total;
-    int num_server_overwrites_total;
-
-    // Count of empty and non empty getupdates;
-    int nonempty_get_updates;
-    int empty_get_updates;
-
-    // Count of useless and useful syncs we perform.
-    int useless_sync_cycles;
-    int useful_sync_cycles;
-
-    // Encryption related.
-    syncable::ModelTypeSet encrypted_types;
-    bool cryptographer_ready;
-    bool crypto_has_pending_keys;
-  };
-
-  // An interface the embedding application implements to receive notifications
-  // from the SyncManager.  Register an observer via SyncManager::AddObserver.
-  // This observer is an event driven model as the events may be raised from
-  // different internal threads, and simply providing an "OnStatusChanged" type
-  // notification complicates things such as trying to determine "what changed",
-  // if different members of the Status object are modified from different
-  // threads.  This way, the event is explicit, and it is safe for the Observer
-  // to dispatch to a native thread or synchronize accordingly.
-  class Observer {
-   public:
-    // Notify the observer that changes have been applied to the sync model.
-    //
-    // This will be invoked on the same thread as on which ApplyChanges was
-    // called. |changes| is an array of size |change_count|, and contains the
-    // ID of each individual item that was changed. |changes| exists only for
-    // the duration of the call. If items of multiple data types change at
-    // the same time, this method is invoked once per data type and |changes|
-    // is restricted to items of the ModelType indicated by |model_type|.
-    // Because the observer is passed a |trans|, the observer can assume a
-    // read lock on the sync model that will be released after the function
-    // returns.
-    //
-    // The SyncManager constructs |changes| in the following guaranteed order:
-    //
-    // 1. Deletions, from leaves up to parents.
-    // 2. Updates to existing items with synced parents & predecessors.
-    // 3. New items with synced parents & predecessors.
-    // 4. Items with parents & predecessors in |changes|.
-    // 5. Repeat #4 until all items are in |changes|.
-    //
-    // Thus, an implementation of OnChangesApplied should be able to
-    // process the change records in the order without having to worry about
-    // forward dependencies.  But since deletions come before reparent
-    // operations, a delete may temporarily orphan a node that is
-    // updated later in the list.
-    virtual void OnChangesApplied(syncable::ModelType model_type,
-                                  const BaseTransaction* trans,
-                                  const ChangeRecord* changes,
-                                  int change_count) = 0;
-
-    // OnChangesComplete gets called when the TransactionComplete event is
-    // posted (after OnChangesApplied finishes), after the transaction lock
-    // and the change channel mutex are released.
-    //
-    // The purpose of this function is to support processors that require
-    // split-transactions changes. For example, if a model processor wants to
-    // perform blocking I/O due to a change, it should calculate the changes
-    // while holding the transaction lock (from within OnChangesApplied), buffer
-    // those changes, let the transaction fall out of scope, and then commit
-    // those changes from within OnChangesComplete (postponing the blocking
-    // I/O to when it no longer holds any lock).
-    virtual void OnChangesComplete(syncable::ModelType model_type) = 0;
-
-    // A round-trip sync-cycle took place and the syncer has resolved any
-    // conflicts that may have arisen.
-    virtual void OnSyncCycleCompleted(
-        const browser_sync::sessions::SyncSessionSnapshot* snapshot) = 0;
-
-    // Called when user interaction may be required due to an auth problem.
-    virtual void OnAuthError(const GoogleServiceAuthError& auth_error) = 0;
-
-    // Called when a new auth token is provided by the sync server.
-    virtual void OnUpdatedToken(const std::string& token) = 0;
-
-    // Called when user interaction is required to obtain a valid passphrase.
-    // - If the passphrase is required for encryption, |reason| will be
-    //   REASON_ENCRYPTION.
-    // - If the passphrase is required for the decryption of data that has
-    //   already been encrypted, |reason| will be REASON_DECRYPTION.
-    // - If the passphrase is required because decryption failed, and a new
-    //   passphrase is required, |reason| will be REASON_SET_PASSPHRASE_FAILED.
-    virtual void OnPassphraseRequired(PassphraseRequiredReason reason) = 0;
-
-    // Called when the passphrase provided by the user has been accepted and is
-    // now used to encrypt sync data.  |bootstrap_token| is an opaque base64
-    // encoded representation of the key generated by the accepted passphrase,
-    // and is provided to the observer for persistence purposes and use in a
-    // future initialization of sync (e.g. after restart).
-    virtual void OnPassphraseAccepted(const std::string& bootstrap_token) = 0;
-
-    // Called when initialization is complete to the point that SyncManager can
-    // process changes. This does not necessarily mean authentication succeeded
-    // or that the SyncManager is online.
-    // IMPORTANT: Creating any type of transaction before receiving this
-    // notification is illegal!
-    // WARNING: Calling methods on the SyncManager before receiving this
-    // message, unless otherwise specified, produces undefined behavior.
-    //
-    // |js_backend| is what about:sync interacts with.  It can emit
-    // the following events:
-
-    /**
-     * @param {{ enabled: boolean }} details A dictionary containing:
-     *     - enabled: whether or not notifications are enabled.
-     */
-    // function onNotificationStateChange(details);
-
-    /**
-     * @param {{ changedTypes: Array.<string> }} details A dictionary
-     *     containing:
-     *     - changedTypes: a list of types (as strings) for which there
-             are new updates.
-     */
-    // function onIncomingNotification(details);
-
-    // Also, it responds to the following messages (all other messages
-    // are ignored):
-
-    /**
-     * Gets the current notification state.
-     *
-     * @param {function(boolean)} callback Called with whether or not
-     *     notifications are enabled.
-     */
-    // function getNotificationState(callback);
-
-    /**
-     * Gets details about the root node.
-     *
-     * @param {function(!Object)} callback Called with details about the
-     *     root node.
-     */
-    // TODO(akalin): Change this to getRootNodeId or eliminate it
-    // entirely.
-    // function getRootNodeDetails(callback);
-
-    /**
-     * Gets summary information for a list of ids.
-     *
-     * @param {Array.<string>} idList List of 64-bit ids in decimal
-     *     string form.
-     * @param {Array.<{id: string, title: string, isFolder: boolean}>}
-     * callback Called with summaries for the nodes in idList that
-     *     exist.
-     */
-    // function getNodeSummariesById(idList, callback);
-
-    /**
-     * Gets detailed information for a list of ids.
-     *
-     * @param {Array.<string>} idList List of 64-bit ids in decimal
-     *     string form.
-     * @param {Array.<!Object>} callback Called with detailed
-     *     information for the nodes in idList that exist.
-     */
-    // function getNodeDetailsById(idList, callback);
-
-    /**
-     * Gets child ids for a given id.
-     *
-     * @param {string} id 64-bit id in decimal string form of the parent
-     *     node.
-     * @param {Array.<string>} callback Called with the (possibly empty)
-     *     list of child ids.
-     */
-    // function getChildNodeIds(id);
-
-    virtual void OnInitializationComplete(
-        const browser_sync::WeakHandle<browser_sync::JsBackend>&
-            js_backend) = 0;
-
-    // We are no longer permitted to communicate with the server. Sync should
-    // be disabled and state cleaned up at once.  This can happen for a number
-    // of reasons, e.g. swapping from a test instance to production, or a
-    // global stop syncing operation has wiped the store.
-    virtual void OnStopSyncingPermanently() = 0;
-
-    // After a request to clear server data, these callbacks are invoked to
-    // indicate success or failure.
-    virtual void OnClearServerDataSucceeded() = 0;
-    virtual void OnClearServerDataFailed() = 0;
-
-    // Called after we finish encrypting all appropriate datatypes.
-    virtual void OnEncryptionComplete(
-        const syncable::ModelTypeSet& encrypted_types) = 0;
-
-   protected:
-    virtual ~Observer();
-  };
-
-  typedef Callback0::Type ModeChangeCallback;
-
-  // Create an uninitialized SyncManager.  Callers must Init() before using.
-  explicit SyncManager(const std::string& name);
-  virtual ~SyncManager();
-
-  // Initialize the sync manager.  |database_location| specifies the path of
-  // the directory in which to locate a sqlite repository storing the syncer
-  // backend state. Initialization will open the database, or create it if it
-  // does not already exist. Returns false on failure.
-  // |event_handler| is the JsEventHandler used to propagate events to
-  // chrome://sync-internals.  |event_handler| may be uninitialized.
-  // |sync_server_and_path| and |sync_server_port| represent the Chrome sync
-  // server to use, and |use_ssl| specifies whether to communicate securely;
-  // the default is false.
-  // |post_factory| will be owned internally and used to create
-  // instances of an HttpPostProvider.
-  // |model_safe_worker| ownership is given to the SyncManager.
-  // |user_agent| is a 7-bit ASCII string suitable for use as the User-Agent
-  // HTTP header. Used internally when collecting stats to classify clients.
-  // |sync_notifier| is owned and used to listen for notifications.
-  bool Init(const FilePath& database_location,
-            const browser_sync::WeakHandle<browser_sync::JsEventHandler>&
-                event_handler,
-            const std::string& sync_server_and_path,
-            int sync_server_port,
-            bool use_ssl,
-            HttpPostProviderFactory* post_factory,
-            browser_sync::ModelSafeWorkerRegistrar* registrar,
-            const std::string& user_agent,
-            const SyncCredentials& credentials,
-            sync_notifier::SyncNotifier* sync_notifier,
-            const std::string& restored_key_for_bootstrapping,
-            bool setup_for_test_mode);
-
-  // Returns the username last used for a successful authentication.
-  // Returns empty if there is no such username.
-  const std::string& GetAuthenticatedUsername();
-
-  // Check if the database has been populated with a full "initial" download of
-  // sync items for each data type currently present in the routing info.
-  // Prerequisite for calling this is that OnInitializationComplete has been
-  // called.
-  bool InitialSyncEndedForAllEnabledTypes();
-
-  // Update tokens that we're using in Sync. Email must stay the same.
-  void UpdateCredentials(const SyncCredentials& credentials);
-
-  // Called when the user disables or enables a sync type.
-  void UpdateEnabledTypes();
-
-  // Put the syncer in normal mode ready to perform nudges and polls.
-  void StartSyncingNormally();
-
-  // Attempt to set the passphrase. If the passphrase is valid,
-  // OnPassphraseAccepted will be fired to notify the ProfileSyncService and the
-  // syncer will be nudged so that any update that was waiting for this
-  // passphrase gets applied as soon as possible.
-  // If the passphrase in invalid, OnPassphraseRequired will be fired.
-  // Calling this metdod again is the appropriate course of action to "retry"
-  // with a new passphrase.
-  // |is_explicit| is true if the call is in response to the user explicitly
-  // setting a passphrase as opposed to implicitly (from the users' perspective)
-  // using their Google Account password.  An implicit SetPassphrase will *not*
-  // *not* override an explicit passphrase set previously.
-  void SetPassphrase(const std::string& passphrase, bool is_explicit);
-
-  // Set the datatypes we want to encrypt and encrypt any nodes as necessary.
-  // Note: |encrypted_types| will be unioned with the current set of encrypted
-  // types, as we do not currently support decrypting datatypes.
-  void EncryptDataTypes(const syncable::ModelTypeSet& encrypted_types);
-
-  // Puts the SyncScheduler into a mode where no normal nudge or poll traffic
-  // will occur, but calls to RequestConfig will be supported.  If |callback|
-  // is provided, it will be invoked (from the internal SyncScheduler) when
-  // the thread has changed to configuration mode.
-  void StartConfigurationMode(ModeChangeCallback* callback);
-
-  // Switches the mode of operation to CONFIGURATION_MODE and
-  // schedules a config task to fetch updates for |types|.
-  void RequestConfig(const syncable::ModelTypeBitSet& types,
-     sync_api::ConfigureReason reason);
-
-  void RequestCleanupDisabledTypes();
-
-  // Request a clearing of all data on the server
-  void RequestClearServerData();
-
-  // Adds a listener to be notified of sync events.
-  // NOTE: It is OK (in fact, it's probably a good idea) to call this before
-  // having received OnInitializationCompleted.
-  void AddObserver(Observer* observer);
-
-  // Remove the given observer.  Make sure to call this if the
-  // Observer is being destroyed so the SyncManager doesn't
-  // potentially dereference garbage.
-  void RemoveObserver(Observer* observer);
-
-  // Status-related getters. Typically GetStatusSummary will suffice, but
-  // GetDetailedSyncStatus can be useful for gathering debug-level details of
-  // the internals of the sync engine.
-  Status::Summary GetStatusSummary() const;
-  Status GetDetailedStatus() const;
-
-  // Whether or not the Nigori node is encrypted using an explicit passphrase.
-  bool IsUsingExplicitPassphrase();
-
-  // Get the internal implementation for use by BaseTransaction, etc.
-  SyncInternal* GetImpl() const;
-
-  // Call periodically from a database-safe thread to persist recent changes
-  // to the syncapi model.
-  void SaveChanges();
-
-  void RequestEarlyExit();
-
-  // Issue a final SaveChanges, close sqlite handles, and stop running threads.
-  // Must be called from the same thread that called Init().
-  void Shutdown();
-
-  UserShare* GetUserShare() const;
-
-  // Inform the cryptographer of the most recent passphrase and set of encrypted
-  // types (from nigori node), then ensure all data that needs encryption is
-  // encrypted with the appropriate passphrase.
-  // Note: opens a transaction and can trigger ON_PASSPHRASE_REQUIRED, so must
-  // only be called after syncapi has been initialized.
-  void RefreshEncryption();
-
-  syncable::ModelTypeSet GetEncryptedDataTypes() const;
-
-  // Uses a read-only transaction to determine if the directory being synced has
-  // any remaining unsynced items.
-  bool HasUnsyncedItems() const;
-
-  // Logs the list of unsynced meta handles.
-  void LogUnsyncedItems(int level) const;
-
-  // Functions used for testing.
-
-  void TriggerOnNotificationStateChangeForTest(
-      bool notifications_enabled);
-
-  void TriggerOnIncomingNotificationForTest(
-      const syncable::ModelTypeBitSet& model_types);
-
- private:
-  // An opaque pointer to the nested private class.
-  SyncInternal* data_;
-
-  DISALLOW_COPY_AND_ASSIGN(SyncManager);
-};
-
-}  // namespace sync_api
-
-#endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_H_
diff --git a/chrome/browser/sync/engine/syncapi_internal.cc b/chrome/browser/sync/engine/syncapi_internal.cc
new file mode 100644
index 0000000..aeb97fc
--- /dev/null
+++ b/chrome/browser/sync/engine/syncapi_internal.cc
@@ -0,0 +1,78 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/engine/syncapi_internal.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/sync/util/cryptographer.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+
+using browser_sync::Cryptographer;
+
+namespace sync_api {
+
+sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
+    const sync_pb::EntitySpecifics& specifics, Cryptographer* crypto) {
+  if (!specifics.HasExtension(sync_pb::password))
+    return NULL;
+  const sync_pb::PasswordSpecifics& password_specifics =
+      specifics.GetExtension(sync_pb::password);
+  if (!password_specifics.has_encrypted())
+    return NULL;
+  const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();
+  scoped_ptr<sync_pb::PasswordSpecificsData> data(
+      new sync_pb::PasswordSpecificsData);
+  if (!crypto->Decrypt(encrypted, data.get()))
+    return NULL;
+  return data.release();
+}
+
+// The list of names which are reserved for use by the server.
+static const char* kForbiddenServerNames[] = { "", ".", ".." };
+
+// Checks whether |name| is a server-illegal name followed by zero or more space
+// characters.  The three server-illegal names are the empty string, dot, and
+// dot-dot.  Very long names (>255 bytes in UTF-8 Normalization Form C) are
+// also illegal, but are not considered here.
+bool IsNameServerIllegalAfterTrimming(const std::string& name) {
+  size_t untrimmed_count = name.find_last_not_of(' ') + 1;
+  for (size_t i = 0; i < arraysize(kForbiddenServerNames); ++i) {
+    if (name.compare(0, untrimmed_count, kForbiddenServerNames[i]) == 0)
+      return true;
+  }
+  return false;
+}
+
+// Compare the values of two EntitySpecifics, accounting for encryption.
+bool AreSpecificsEqual(const browser_sync::Cryptographer* cryptographer,
+                       const sync_pb::EntitySpecifics& left,
+                       const sync_pb::EntitySpecifics& right) {
+  // Note that we can't compare encrypted strings directly as they are seeded
+  // with a random value.
+  std::string left_plaintext, right_plaintext;
+  if (left.has_encrypted()) {
+    if (!cryptographer->CanDecrypt(left.encrypted())) {
+      NOTREACHED() << "Attempting to compare undecryptable data.";
+      return false;
+    }
+    left_plaintext = cryptographer->DecryptToString(left.encrypted());
+  } else {
+    left_plaintext = left.SerializeAsString();
+  }
+  if (right.has_encrypted()) {
+    if (!cryptographer->CanDecrypt(right.encrypted())) {
+      NOTREACHED() << "Attempting to compare undecryptable data.";
+      return false;
+    }
+    right_plaintext = cryptographer->DecryptToString(right.encrypted());
+  } else {
+    right_plaintext = right.SerializeAsString();
+  }
+  if (left_plaintext == right_plaintext) {
+    return true;
+  }
+  return false;
+}
+
+} // namespace sync_api
diff --git a/chrome/browser/sync/engine/syncapi_internal.h b/chrome/browser/sync/engine/syncapi_internal.h
new file mode 100644
index 0000000..aa4cf0b0
--- /dev/null
+++ b/chrome/browser/sync/engine/syncapi_internal.h
@@ -0,0 +1,34 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_INTERNAL_H_
+#define CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_INTERNAL_H_
+
+// The functions defined are shared among some of the classes that implement
+// the internal sync_api.  They are not to be used by clients of the API.
+
+#include <string>
+
+namespace browser_sync {
+class Cryptographer;
+}
+
+namespace sync_pb {
+class EntitySpecifics;
+class PasswordSpecificsData;
+}
+
+namespace sync_api {
+sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
+    const sync_pb::EntitySpecifics& specifics,
+    browser_sync::Cryptographer* crypto);
+
+bool IsNameServerIllegalAfterTrimming(const std::string& name);
+
+bool AreSpecificsEqual(const browser_sync::Cryptographer* cryptographer,
+                       const sync_pb::EntitySpecifics& left,
+                       const sync_pb::EntitySpecifics& right);
+}
+
+#endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_INTERNAL_H_
diff --git a/chrome/browser/sync/glue/app_change_processor.cc b/chrome/browser/sync/glue/app_change_processor.cc
index e8f4009..609bc8b 100644
--- a/chrome/browser/sync/glue/app_change_processor.cc
+++ b/chrome/browser/sync/glue/app_change_processor.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/glue/extension_sync.h"
 #include "chrome/browser/sync/glue/extension_util.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
 #include "chrome/browser/sync/protocol/extension_specifics.pb.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 #include "chrome/common/chrome_notification_types.h"
diff --git a/chrome/browser/sync/glue/app_change_processor.h b/chrome/browser/sync/glue/app_change_processor.h
index 7c2ce3e..0a692a8 100644
--- a/chrome/browser/sync/glue/app_change_processor.h
+++ b/chrome/browser/sync/glue/app_change_processor.h
@@ -7,9 +7,9 @@
 #pragma once
 
 #include "base/basictypes.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/extension_sync_traits.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "content/common/content_notification_types.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
diff --git a/chrome/browser/sync/glue/app_model_associator.cc b/chrome/browser/sync/glue/app_model_associator.cc
index 633c680..1130e6a 100644
--- a/chrome/browser/sync/glue/app_model_associator.cc
+++ b/chrome/browser/sync/glue/app_model_associator.cc
@@ -8,9 +8,10 @@
 #include "base/tracked.h"
 #include "chrome/browser/extensions/extension_sync_data.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
-#include "chrome/browser/sync/glue/extension_sync_traits.h"
 #include "chrome/browser/sync/glue/extension_sync.h"
+#include "chrome/browser/sync/glue/extension_sync_traits.h"
+#include "chrome/browser/sync/glue/extension_sync_traits.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/extension_specifics.pb.h"
 #include "content/browser/browser_thread.h"
diff --git a/chrome/browser/sync/glue/autofill_change_processor.cc b/chrome/browser/sync/glue/autofill_change_processor.cc
index a3dc858..6c4812a 100644
--- a/chrome/browser/sync/glue/autofill_change_processor.cc
+++ b/chrome/browser/sync/glue/autofill_change_processor.cc
@@ -15,11 +15,14 @@
 #include "chrome/browser/sync/glue/autofill_model_associator.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/do_optimistic_refresh_task.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/webdata/autofill_change.h"
 #include "chrome/browser/webdata/autofill_table.h"
-#include "chrome/browser/webdata/web_data_service.h"
 #include "chrome/browser/webdata/web_database.h"
+#include "chrome/browser/webdata/web_data_service.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/guid.h"
 #include "content/common/notification_service.h"
diff --git a/chrome/browser/sync/glue/autofill_change_processor.h b/chrome/browser/sync/glue/autofill_change_processor.h
index 1ea0e1a..70325a4 100644
--- a/chrome/browser/sync/glue/autofill_change_processor.h
+++ b/chrome/browser/sync/glue/autofill_change_processor.h
@@ -11,9 +11,9 @@
 #include "chrome/browser/autofill/autofill_profile.h"
 #include "chrome/browser/autofill/credit_card.h"
 #include "chrome/browser/autofill/personal_data_manager.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
 #include "chrome/browser/webdata/web_data_service.h"
 #include "content/common/notification_observer.h"
@@ -25,6 +25,12 @@ class AutofillProfileChange;
 class PersonalDataManager;
 class WebDatabase;
 
+namespace sync_api {
+class ReadNode;
+class WriteNode;
+class WriteTransaction;
+}  // namespace sync_api
+
 namespace browser_sync {
 
 class AutofillModelAssociator;
diff --git a/chrome/browser/sync/glue/autofill_model_associator.cc b/chrome/browser/sync/glue/autofill_model_associator.cc
index 3b8ef96..0ec8b06 100644
--- a/chrome/browser/sync/glue/autofill_model_associator.cc
+++ b/chrome/browser/sync/glue/autofill_model_associator.cc
@@ -15,10 +15,13 @@
 #include "chrome/browser/autofill/autofill_profile.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/autofill_change_processor.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/do_optimistic_refresh_task.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
 #include "chrome/browser/webdata/autofill_table.h"
diff --git a/chrome/browser/sync/glue/autofill_model_associator.h b/chrome/browser/sync/glue/autofill_model_associator.h
index baffaa8..1de7848 100644
--- a/chrome/browser/sync/glue/autofill_model_associator.h
+++ b/chrome/browser/sync/glue/autofill_model_associator.h
@@ -15,7 +15,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/autofill/personal_data_manager.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/model_associator.h"
 #include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
 #include "chrome/browser/webdata/autofill_entry.h"
@@ -26,6 +25,7 @@ class ProfileSyncService;
 class WebDatabase;
 
 namespace sync_api {
+class ReadNode;
 class WriteTransaction;
 }
 
diff --git a/chrome/browser/sync/glue/autofill_profile_change_processor.cc b/chrome/browser/sync/glue/autofill_profile_change_processor.cc
index 1bd00a3..1dfe3ca 100644
--- a/chrome/browser/sync/glue/autofill_profile_change_processor.cc
+++ b/chrome/browser/sync/glue/autofill_profile_change_processor.cc
@@ -12,10 +12,13 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/autofill/autofill_profile.h"
 #include "chrome/browser/autofill/personal_data_manager.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/do_optimistic_refresh_task.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 #include "chrome/browser/webdata/autofill_change.h"
 #include "chrome/browser/webdata/autofill_table.h"
diff --git a/chrome/browser/sync/glue/autofill_profile_change_processor.h b/chrome/browser/sync/glue/autofill_profile_change_processor.h
index c9fd9fe..1f4a6fb 100644
--- a/chrome/browser/sync/glue/autofill_profile_change_processor.h
+++ b/chrome/browser/sync/glue/autofill_profile_change_processor.h
@@ -10,9 +10,9 @@
 
 #include "chrome/browser/autofill/autofill_profile.h"
 #include "chrome/browser/autofill/personal_data_manager.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/change_processor.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 #include "chrome/browser/webdata/autofill_change.h"
 #include "chrome/browser/webdata/web_database.h"
@@ -21,6 +21,12 @@
 #include "content/common/notification_registrar.h"
 #include "content/common/notification_service.h"
 
+namespace sync_api {
+class ReadNode;
+class WriteNode;
+class WriteTransaction;
+}  // namespace sync_api
+
 namespace browser_sync {
 
 class AutofillProfileChangeProcessor : public ChangeProcessor,
diff --git a/chrome/browser/sync/glue/autofill_profile_model_associator.cc b/chrome/browser/sync/glue/autofill_profile_model_associator.cc
index 0197f93..6f08cc4 100644
--- a/chrome/browser/sync/glue/autofill_profile_model_associator.cc
+++ b/chrome/browser/sync/glue/autofill_profile_model_associator.cc
@@ -9,6 +9,10 @@
 #include "chrome/browser/sync/api/sync_error.h"
 #include "chrome/browser/sync/glue/autofill_profile_change_processor.h"
 #include "chrome/browser/sync/glue/do_optimistic_refresh_task.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/webdata/autofill_table.h"
 #include "chrome/browser/webdata/web_database.h"
diff --git a/chrome/browser/sync/glue/autofill_profile_model_associator.h b/chrome/browser/sync/glue/autofill_profile_model_associator.h
index 4b0b1a2..af1e9c2 100644
--- a/chrome/browser/sync/glue/autofill_profile_model_associator.h
+++ b/chrome/browser/sync/glue/autofill_profile_model_associator.h
@@ -15,7 +15,6 @@
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/autofill/personal_data_manager.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/model_associator.h"
 #include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
 #include "chrome/browser/webdata/autofill_entry.h"
@@ -26,8 +25,9 @@ class ProfileSyncService;
 class WebDatabase;
 
 namespace sync_api {
+class ReadNode;
 class WriteTransaction;
-}
+}  // namespace sync_api
 
 namespace browser_sync {
 
diff --git a/chrome/browser/sync/glue/autofill_profile_model_associator_unittest.cc b/chrome/browser/sync/glue/autofill_profile_model_associator_unittest.cc
index 909b895..312fccd 100644
--- a/chrome/browser/sync/glue/autofill_profile_model_associator_unittest.cc
+++ b/chrome/browser/sync/glue/autofill_profile_model_associator_unittest.cc
@@ -4,8 +4,8 @@
 
 #include "base/tracked.h"
 #include "base/utf_string_conversions.h"
-#include "chrome/browser/sync/engine/read_node_mock.h"
-#include "chrome/browser/sync/engine/syncapi_mock.h"
+#include "chrome/browser/sync/internal_api/read_node_mock.h"
+#include "chrome/browser/sync/internal_api/syncapi_mock.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/syncable/syncable.h"
 #include "chrome/browser/sync/syncable/syncable_mock.h"
diff --git a/chrome/browser/sync/glue/bookmark_change_processor.cc b/chrome/browser/sync/glue/bookmark_change_processor.cc
index 0e74619..a530f81 100644
--- a/chrome/browser/sync/glue/bookmark_change_processor.cc
+++ b/chrome/browser/sync/glue/bookmark_change_processor.cc
@@ -15,6 +15,9 @@
 #include "chrome/browser/bookmarks/bookmark_utils.h"
 #include "chrome/browser/favicon/favicon_service.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "content/browser/browser_thread.h"
 #include "third_party/skia/include/core/SkBitmap.h"
diff --git a/chrome/browser/sync/glue/bookmark_change_processor.h b/chrome/browser/sync/glue/bookmark_change_processor.h
index 8802716..5f242fd 100644
--- a/chrome/browser/sync/glue/bookmark_change_processor.h
+++ b/chrome/browser/sync/glue/bookmark_change_processor.h
@@ -9,10 +9,15 @@
 #include <vector>
 
 #include "chrome/browser/bookmarks/bookmark_model_observer.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/bookmark_model_associator.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+
+namespace sync_api {
+class WriteNode;
+class WriteTransaction;
+}  // namespace sync_api
 
 namespace browser_sync {
 
diff --git a/chrome/browser/sync/glue/bookmark_model_associator.cc b/chrome/browser/sync/glue/bookmark_model_associator.cc
index 137bb66..faa377b 100644
--- a/chrome/browser/sync/glue/bookmark_model_associator.cc
+++ b/chrome/browser/sync/glue/bookmark_model_associator.cc
@@ -15,8 +15,11 @@
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/bookmark_change_processor.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/util/cryptographer.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/browser/browser_thread.h"
diff --git a/chrome/browser/sync/glue/change_processor.h b/chrome/browser/sync/glue/change_processor.h
index fba8301..d525281 100644
--- a/chrome/browser/sync/glue/change_processor.h
+++ b/chrome/browser/sync/glue/change_processor.h
@@ -6,8 +6,8 @@
 #define CHROME_BROWSER_SYNC_GLUE_CHANGE_PROCESSOR_H_
 #pragma once
 
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 
 class Profile;
 
diff --git a/chrome/browser/sync/glue/change_processor_mock.h b/chrome/browser/sync/glue/change_processor_mock.h
index 65696aa..10d62cd 100644
--- a/chrome/browser/sync/glue/change_processor_mock.h
+++ b/chrome/browser/sync/glue/change_processor_mock.h
@@ -6,8 +6,9 @@
 #define CHROME_BROWSER_SYNC_GLUE_CHANGE_PROCESSOR_MOCK_H__
 #pragma once
 
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/syncable/syncable.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 class Profile;
diff --git a/chrome/browser/sync/glue/extension_change_processor.cc b/chrome/browser/sync/glue/extension_change_processor.cc
index 71043a0..9fddd3e 100644
--- a/chrome/browser/sync/glue/extension_change_processor.cc
+++ b/chrome/browser/sync/glue/extension_change_processor.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/glue/extension_sync.h"
 #include "chrome/browser/sync/glue/extension_util.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
 #include "chrome/browser/sync/protocol/extension_specifics.pb.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 #include "chrome/common/chrome_notification_types.h"
diff --git a/chrome/browser/sync/glue/extension_change_processor.h b/chrome/browser/sync/glue/extension_change_processor.h
index f2493be..e223b92 100644
--- a/chrome/browser/sync/glue/extension_change_processor.h
+++ b/chrome/browser/sync/glue/extension_change_processor.h
@@ -7,9 +7,9 @@
 #pragma once
 
 #include "base/basictypes.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/extension_sync_traits.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "content/common/content_notification_types.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
diff --git a/chrome/browser/sync/glue/extension_model_associator.cc b/chrome/browser/sync/glue/extension_model_associator.cc
index 46421b7..0856e46 100644
--- a/chrome/browser/sync/glue/extension_model_associator.cc
+++ b/chrome/browser/sync/glue/extension_model_associator.cc
@@ -7,9 +7,10 @@
 #include "base/logging.h"
 #include "base/tracked.h"
 #include "chrome/browser/extensions/extension_sync_data.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/extension_sync_traits.h"
 #include "chrome/browser/sync/glue/extension_sync.h"
+#include "chrome/browser/sync/glue/extension_sync_traits.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/extension_specifics.pb.h"
 #include "content/browser/browser_thread.h"
diff --git a/chrome/browser/sync/glue/extension_sync.cc b/chrome/browser/sync/glue/extension_sync.cc
index c6c19ec..d057d6a 100644
--- a/chrome/browser/sync/glue/extension_sync.cc
+++ b/chrome/browser/sync/glue/extension_sync.cc
@@ -10,9 +10,12 @@
 #include "base/tracked.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_sync_data.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/extension_sync_traits.h"
 #include "chrome/browser/sync/glue/extension_util.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/protocol/extension_specifics.pb.h"
 
 namespace browser_sync {
diff --git a/chrome/browser/sync/glue/extension_sync_traits.cc b/chrome/browser/sync/glue/extension_sync_traits.cc
index eae2425..3ef4eda 100644
--- a/chrome/browser/sync/glue/extension_sync_traits.cc
+++ b/chrome/browser/sync/glue/extension_sync_traits.cc
@@ -6,8 +6,8 @@
 
 #include "base/string_piece.h"
 #include "base/utf_string_conversions.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/extension_util.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
 #include "chrome/browser/sync/protocol/app_specifics.pb.h"
 #include "chrome/browser/sync/protocol/extension_specifics.pb.h"
 #include "chrome/common/extensions/extension.h"
diff --git a/chrome/browser/sync/glue/generic_change_processor.cc b/chrome/browser/sync/glue/generic_change_processor.cc
index 075d700..dd1aea0 100644
--- a/chrome/browser/sync/glue/generic_change_processor.cc
+++ b/chrome/browser/sync/glue/generic_change_processor.cc
@@ -9,7 +9,11 @@
 #include "chrome/browser/sync/api/syncable_service.h"
 #include "chrome/browser/sync/api/sync_change.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 
 namespace browser_sync {
diff --git a/chrome/browser/sync/glue/http_bridge.h b/chrome/browser/sync/glue/http_bridge.h
index d28699f..ed95c72 100644
--- a/chrome/browser/sync/glue/http_bridge.h
+++ b/chrome/browser/sync/glue/http_bridge.h
@@ -15,11 +15,10 @@
 #include "base/synchronization/waitable_event.h"
 #include "chrome/browser/sync/engine/http_post_provider_factory.h"
 #include "chrome/browser/sync/engine/http_post_provider_interface.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "content/common/url_fetcher.h"
 #include "googleurl/src/gurl.h"
-#include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "net/url_request/url_request_context.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class MessageLoop;
diff --git a/chrome/browser/sync/glue/password_change_processor.cc b/chrome/browser/sync/glue/password_change_processor.cc
index d2f4d13..838cf39 100644
--- a/chrome/browser/sync/glue/password_change_processor.cc
+++ b/chrome/browser/sync/glue/password_change_processor.cc
@@ -9,10 +9,13 @@
 #include "base/string_util.h"
 #include "base/tracked.h"
 #include "base/utf_string_conversions.h"
-#include "chrome/browser/password_manager/password_store.h"
 #include "chrome/browser/password_manager/password_store_change.h"
+#include "chrome/browser/password_manager/password_store.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/glue/password_model_associator.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/password_specifics.pb.h"
 #include "chrome/common/chrome_notification_types.h"
diff --git a/chrome/browser/sync/glue/password_model_associator.cc b/chrome/browser/sync/glue/password_model_associator.cc
index 6d96186..b853b3f 100644
--- a/chrome/browser/sync/glue/password_model_associator.cc
+++ b/chrome/browser/sync/glue/password_model_associator.cc
@@ -11,7 +11,10 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/password_manager/password_store.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/password_specifics.pb.h"
 #include "net/base/escape.h"
diff --git a/chrome/browser/sync/glue/session_change_processor.cc b/chrome/browser/sync/glue/session_change_processor.cc
index b889853..39b2e8e 100644
--- a/chrome/browser/sync/glue/session_change_processor.cc
+++ b/chrome/browser/sync/glue/session_change_processor.cc
@@ -12,8 +12,9 @@
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/extensions/extension_tab_helper.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/session_model_associator.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/common/chrome_notification_types.h"
diff --git a/chrome/browser/sync/glue/session_change_processor.h b/chrome/browser/sync/glue/session_change_processor.h
index 62fa5c8..35010ef 100644
--- a/chrome/browser/sync/glue/session_change_processor.h
+++ b/chrome/browser/sync/glue/session_change_processor.h
@@ -9,8 +9,8 @@
 #include "base/basictypes.h"
 #include "chrome/browser/sessions/session_backend.h"
 #include "chrome/browser/sessions/session_service.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "content/common/content_notification_types.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
diff --git a/chrome/browser/sync/glue/session_model_associator.cc b/chrome/browser/sync/glue/session_model_associator.cc
index 227b5ee..4b7496d 100644
--- a/chrome/browser/sync/glue/session_model_associator.cc
+++ b/chrome/browser/sync/glue/session_model_associator.cc
@@ -15,6 +15,10 @@
 #include "chrome/browser/sync/api/sync_error.h"
 #include "chrome/browser/sync/glue/synced_tab_delegate.h"
 #include "chrome/browser/sync/glue/synced_window_delegate.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/syncable/syncable.h"
 #include "chrome/common/chrome_notification_types.h"
diff --git a/chrome/browser/sync/glue/session_model_associator.h b/chrome/browser/sync/glue/session_model_associator.h
index 83ea9ef..9579140 100644
--- a/chrome/browser/sync/glue/session_model_associator.h
+++ b/chrome/browser/sync/glue/session_model_associator.h
@@ -21,11 +21,10 @@
 #include "chrome/browser/sessions/session_id.h"
 #include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_types.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/glue/model_associator.h"
 #include "chrome/browser/sync/glue/synced_session_tracker.h"
 #include "chrome/browser/sync/glue/synced_tab_delegate.h"
 #include "chrome/browser/sync/glue/synced_window_delegate.h"
-#include "chrome/browser/sync/glue/model_associator.h"
 #include "chrome/browser/sync/protocol/session_specifics.pb.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 
@@ -33,6 +32,7 @@ class Profile;
 class ProfileSyncService;
 
 namespace sync_api {
+class BaseTransaction;
 class ReadNode;
 class WriteNode;
 class WriteTransaction;
diff --git a/chrome/browser/sync/glue/sync_backend_host.cc b/chrome/browser/sync/glue/sync_backend_host.cc
index a4c11cc..116164f 100644
--- a/chrome/browser/sync/glue/sync_backend_host.cc
+++ b/chrome/browser/sync/glue/sync_backend_host.cc
@@ -5,6 +5,7 @@
 #include "build/build_config.h"
 
 #include <algorithm>
+#include <map>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ -17,7 +18,6 @@
 #include "chrome/browser/net/gaia/token_service.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/autofill_model_associator.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/change_processor.h"
@@ -26,6 +26,8 @@
 #include "chrome/browser/sync/glue/http_bridge.h"
 #include "chrome/browser/sync/glue/password_model_worker.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/js/js_arg_list.h"
 #include "chrome/browser/sync/js/js_event_details.h"
 #include "chrome/browser/sync/js/js_event_handler.h"
diff --git a/chrome/browser/sync/glue/sync_backend_host.h b/chrome/browser/sync/glue/sync_backend_host.h
index 9270f75..21fe22a 100644
--- a/chrome/browser/sync/glue/sync_backend_host.h
+++ b/chrome/browser/sync/glue/sync_backend_host.h
@@ -15,6 +15,7 @@
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
@@ -22,6 +23,7 @@
 #include "chrome/browser/sync/engine/configure_reason.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/glue/ui_model_worker.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/js/js_backend.h"
 #include "chrome/browser/sync/notifier/sync_notifier_factory.h"
 #include "chrome/browser/sync/syncable/model_type.h"
diff --git a/chrome/browser/sync/glue/sync_backend_host_unittest.cc b/chrome/browser/sync/glue/sync_backend_host_unittest.cc
index 83aa28c..2bf47d1 100644
--- a/chrome/browser/sync/glue/sync_backend_host_unittest.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_unittest.cc
@@ -9,11 +9,10 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/syncable/model_type.h"
-#include "chrome/test/base/test_url_request_context_getter.h"
 #include "chrome/test/base/testing_browser_process_test.h"
 #include "chrome/test/base/testing_profile.h"
+#include "chrome/test/base/test_url_request_context_getter.h"
 #include "content/browser/browser_thread.h"
 #include "content/common/url_fetcher.h"
 #include "content/test/test_url_fetcher_factory.h"
diff --git a/chrome/browser/sync/glue/theme_change_processor.cc b/chrome/browser/sync/glue/theme_change_processor.cc
index 0783225..6876731 100644
--- a/chrome/browser/sync/glue/theme_change_processor.cc
+++ b/chrome/browser/sync/glue/theme_change_processor.cc
@@ -7,12 +7,15 @@
 #include "base/logging.h"
 #include "base/tracked.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/theme_util.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/protocol/theme_specifics.pb.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
-#include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/themes/theme_service_factory.h"
+#include "chrome/browser/themes/theme_service.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/extensions/extension.h"
 #include "content/common/notification_details.h"
diff --git a/chrome/browser/sync/glue/theme_change_processor.h b/chrome/browser/sync/glue/theme_change_processor.h
index 72c7473..b7c3c9e 100644
--- a/chrome/browser/sync/glue/theme_change_processor.h
+++ b/chrome/browser/sync/glue/theme_change_processor.h
@@ -7,8 +7,8 @@
 #pragma once
 
 #include "base/basictypes.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "content/common/content_notification_types.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
diff --git a/chrome/browser/sync/glue/theme_model_associator.cc b/chrome/browser/sync/glue/theme_model_associator.cc
index 5638bad..6b9ee5a 100644
--- a/chrome/browser/sync/glue/theme_model_associator.cc
+++ b/chrome/browser/sync/glue/theme_model_associator.cc
@@ -9,9 +9,12 @@
 #include "base/tracked.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
 #include "chrome/browser/sync/glue/theme_util.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/theme_specifics.pb.h"
 
diff --git a/chrome/browser/sync/glue/typed_url_change_processor.cc b/chrome/browser/sync/glue/typed_url_change_processor.cc
index f309697..be6767a 100644
--- a/chrome/browser/sync/glue/typed_url_change_processor.cc
+++ b/chrome/browser/sync/glue/typed_url_change_processor.cc
@@ -11,6 +11,9 @@
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/glue/typed_url_model_associator.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/typed_url_specifics.pb.h"
 #include "chrome/common/chrome_notification_types.h"
diff --git a/chrome/browser/sync/glue/typed_url_model_associator.cc b/chrome/browser/sync/glue/typed_url_model_associator.cc
index 08e47d4..0d480ef 100644
--- a/chrome/browser/sync/glue/typed_url_model_associator.cc
+++ b/chrome/browser/sync/glue/typed_url_model_associator.cc
@@ -12,7 +12,10 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/history/history_backend.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/protocol/typed_url_specifics.pb.h"
 
diff --git a/chrome/browser/sync/glue/ui_model_worker.h b/chrome/browser/sync/glue/ui_model_worker.h
index 6a338db..5d0a97daf 100644
--- a/chrome/browser/sync/glue/ui_model_worker.h
+++ b/chrome/browser/sync/glue/ui_model_worker.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -7,10 +7,9 @@
 #pragma once
 
 #include "base/callback.h"
-#include "base/synchronization/lock.h"
 #include "base/synchronization/condition_variable.h"
+#include "base/synchronization/lock.h"
 #include "base/task.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 
 namespace base {
diff --git a/chrome/browser/sync/glue/ui_model_worker_unittest.cc b/chrome/browser/sync/glue/ui_model_worker_unittest.cc
index 05422c9..c0230f1 100644
--- a/chrome/browser/sync/glue/ui_model_worker_unittest.cc
+++ b/chrome/browser/sync/glue/ui_model_worker_unittest.cc
@@ -4,12 +4,12 @@
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
-#include "base/threading/thread.h"
 #include "base/synchronization/waitable_event.h"
-#include "content/browser/browser_thread.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "base/threading/thread.h"
 #include "chrome/browser/sync/glue/ui_model_worker.h"
+#include "content/browser/browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using browser_sync::UIModelWorker;
diff --git a/chrome/browser/sync/internal_api/DEPS b/chrome/browser/sync/internal_api/DEPS
new file mode 100644
index 0000000..ff4b760
--- /dev/null
+++ b/chrome/browser/sync/internal_api/DEPS
@@ -0,0 +1,14 @@
+include_rules = [
+  "-chrome",
+  "+chrome/test/base",
+  "+chrome/test/sync",
+
+  "+chrome/browser/sync",
+  "-chrome/browser/sync/api",
+  "-chrome/browser/sync/glue",
+
+  # unittests need this for mac osx keychain overriding
+  "+chrome/browser/password_manager/encryptor.h",
+
+  "+chrome/common/net/gaia/google_service_auth_error.h",
+]
diff --git a/chrome/browser/sync/internal_api/README b/chrome/browser/sync/internal_api/README
new file mode 100644
index 0000000..32987bb
--- /dev/null
+++ b/chrome/browser/sync/internal_api/README
@@ -0,0 +1,32 @@
+This file defines the "sync API", an interface to the syncer
+backend that exposes (1) the core functionality of maintaining a consistent
+local snapshot of a hierarchical object set; (2) a means to transactionally
+access and modify those objects; (3) a means to control client/server
+synchronization tasks, namely: pushing local object modifications to a
+server, pulling nonlocal object modifications from a server to this client,
+and resolving conflicts that may arise between the two; and (4) an
+abstraction of some external functionality that is to be provided by the
+host environment.
+
+This interface is used as the entry point into the syncer backend
+when the backend is compiled as a library and embedded in another
+application.  A goal for this interface layer is to depend on very few
+external types, so that an application can use the sync backend
+without introducing a dependency on specific types.  A non-goal is to
+have binary compatibility across versions or compilers; this allows the
+interface to use C++ classes.  An application wishing to use the sync API
+should ideally compile the syncer backend and this API as part of the
+application's own build, to avoid e.g. mismatches in calling convention,
+structure padding, or name mangling that could arise if there were a
+compiler mismatch.
+
+The schema of the objects in the sync domain is based on the model, which
+is essentially a hierarchy of items and folders similar to a filesystem,
+but with a few important differences.  The sync API contains fields
+such as URL to easily allow the embedding application to store web
+browser bookmarks.  Also, the sync API allows duplicate titles in a parent.
+Consequently, it does not support looking up an object by title
+and parent, since such a lookup is not uniquely determined.  Lastly,
+unlike a filesystem model, objects in the Sync API model have a strict
+ordering within a parent; the position is manipulable by callers, and
+children of a node can be enumerated in the order of their position.
diff --git a/chrome/browser/sync/internal_api/base_node.cc b/chrome/browser/sync/internal_api/base_node.cc
new file mode 100644
index 0000000..002006c
--- /dev/null
+++ b/chrome/browser/sync/internal_api/base_node.cc
@@ -0,0 +1,298 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/internal_api/base_node.h"
+
+#include "base/base64.h"
+#include "base/sha1.h"
+#include "base/string_number_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/sync/engine/syncapi_internal.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/protocol/app_specifics.pb.h"
+#include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
+#include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
+#include "chrome/browser/sync/protocol/extension_specifics.pb.h"
+#include "chrome/browser/sync/protocol/nigori_specifics.pb.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+#include "chrome/browser/sync/protocol/session_specifics.pb.h"
+#include "chrome/browser/sync/protocol/theme_specifics.pb.h"
+#include "chrome/browser/sync/protocol/typed_url_specifics.pb.h"
+#include "chrome/browser/sync/syncable/directory_manager.h"
+#include "chrome/browser/sync/syncable/syncable.h"
+#include "chrome/browser/sync/syncable/syncable_id.h"
+
+using syncable::SPECIFICS;
+using sync_pb::AutofillProfileSpecifics;
+
+namespace sync_api {
+
+// Helper function to look up the int64 metahandle of an object given the ID
+// string.
+static int64 IdToMetahandle(syncable::BaseTransaction* trans,
+                            const syncable::Id& id) {
+  syncable::Entry entry(trans, syncable::GET_BY_ID, id);
+  if (!entry.good())
+    return kInvalidId;
+  return entry.Get(syncable::META_HANDLE);
+}
+
+static bool EndsWithSpace(const std::string& string) {
+  return !string.empty() && *string.rbegin() == ' ';
+}
+
+// In the reverse direction, if a server name matches the pattern of a
+// server-illegal name followed by one or more spaces, remove the trailing
+// space.
+static void ServerNameToSyncAPIName(const std::string& server_name,
+                                    std::string* out) {
+  CHECK(out);
+  int length_to_copy = server_name.length();
+  if (IsNameServerIllegalAfterTrimming(server_name) &&
+      EndsWithSpace(server_name)) {
+    --length_to_copy;
+  }
+  *out = std::string(server_name.c_str(), length_to_copy);
+}
+
+BaseNode::BaseNode() : password_data_(new sync_pb::PasswordSpecificsData) {}
+
+BaseNode::~BaseNode() {}
+
+std::string BaseNode::GenerateSyncableHash(
+    syncable::ModelType model_type, const std::string& client_tag) {
+  // blank PB with just the extension in it has termination symbol,
+  // handy for delimiter
+  sync_pb::EntitySpecifics serialized_type;
+  syncable::AddDefaultExtensionValue(model_type, &serialized_type);
+  std::string hash_input;
+  serialized_type.AppendToString(&hash_input);
+  hash_input.append(client_tag);
+
+  std::string encode_output;
+  CHECK(base::Base64Encode(base::SHA1HashString(hash_input), &encode_output));
+  return encode_output;
+}
+
+bool BaseNode::DecryptIfNecessary() {
+  if (!GetEntry()->Get(syncable::UNIQUE_SERVER_TAG).empty())
+      return true;  // Ignore unique folders.
+  const sync_pb::EntitySpecifics& specifics =
+      GetEntry()->Get(syncable::SPECIFICS);
+  if (specifics.HasExtension(sync_pb::password)) {
+    // Passwords have their own legacy encryption structure.
+    scoped_ptr<sync_pb::PasswordSpecificsData> data(DecryptPasswordSpecifics(
+        specifics, GetTransaction()->GetCryptographer()));
+    if (!data.get()) {
+      LOG(ERROR) << "Failed to decrypt password specifics.";
+      return false;
+    }
+    password_data_.swap(data);
+    return true;
+  }
+
+  // We assume any node with the encrypted field set has encrypted data.
+  if (!specifics.has_encrypted())
+    return true;
+
+  const sync_pb::EncryptedData& encrypted =
+      specifics.encrypted();
+  std::string plaintext_data = GetTransaction()->GetCryptographer()->
+      DecryptToString(encrypted);
+  if (plaintext_data.length() == 0 ||
+      !unencrypted_data_.ParseFromString(plaintext_data)) {
+    LOG(ERROR) << "Failed to decrypt encrypted node of type " <<
+      syncable::ModelTypeToString(GetModelType()) << ".";
+    return false;
+  }
+  VLOG(2) << "Decrypted specifics of type "
+          << syncable::ModelTypeToString(GetModelType())
+          << " with content: " << plaintext_data;
+  return true;
+}
+
+const sync_pb::EntitySpecifics& BaseNode::GetUnencryptedSpecifics(
+    const syncable::Entry* entry) const {
+  const sync_pb::EntitySpecifics& specifics = entry->Get(SPECIFICS);
+  if (specifics.has_encrypted()) {
+    DCHECK(syncable::GetModelTypeFromSpecifics(unencrypted_data_) !=
+           syncable::UNSPECIFIED);
+    return unencrypted_data_;
+  } else {
+    DCHECK(syncable::GetModelTypeFromSpecifics(unencrypted_data_) ==
+           syncable::UNSPECIFIED);
+    return specifics;
+  }
+}
+
+int64 BaseNode::GetParentId() const {
+  return IdToMetahandle(GetTransaction()->GetWrappedTrans(),
+                        GetEntry()->Get(syncable::PARENT_ID));
+}
+
+int64 BaseNode::GetId() const {
+  return GetEntry()->Get(syncable::META_HANDLE);
+}
+
+int64 BaseNode::GetModificationTime() const {
+  return GetEntry()->Get(syncable::MTIME);
+}
+
+bool BaseNode::GetIsFolder() const {
+  return GetEntry()->Get(syncable::IS_DIR);
+}
+
+std::string BaseNode::GetTitle() const {
+  std::string result;
+  // TODO(zea): refactor bookmarks to not need this functionality.
+  if (syncable::BOOKMARKS == GetModelType() &&
+      GetEntry()->Get(syncable::SPECIFICS).has_encrypted()) {
+    // Special case for legacy bookmarks dealing with encryption.
+    ServerNameToSyncAPIName(GetBookmarkSpecifics().title(), &result);
+  } else {
+    ServerNameToSyncAPIName(GetEntry()->Get(syncable::NON_UNIQUE_NAME),
+                            &result);
+  }
+  return result;
+}
+
+GURL BaseNode::GetURL() const {
+  return GURL(GetBookmarkSpecifics().url());
+}
+
+int64 BaseNode::GetPredecessorId() const {
+  syncable::Id id_string = GetEntry()->Get(syncable::PREV_ID);
+  if (id_string.IsRoot())
+    return kInvalidId;
+  return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
+}
+
+int64 BaseNode::GetSuccessorId() const {
+  syncable::Id id_string = GetEntry()->Get(syncable::NEXT_ID);
+  if (id_string.IsRoot())
+    return kInvalidId;
+  return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
+}
+
+int64 BaseNode::GetFirstChildId() const {
+  syncable::Directory* dir = GetTransaction()->GetLookup();
+  syncable::BaseTransaction* trans = GetTransaction()->GetWrappedTrans();
+  syncable::Id id_string =
+      dir->GetFirstChildId(trans, GetEntry()->Get(syncable::ID));
+  if (id_string.IsRoot())
+    return kInvalidId;
+  return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
+}
+
+DictionaryValue* BaseNode::GetSummaryAsValue() const {
+  DictionaryValue* node_info = new DictionaryValue();
+  node_info->SetString("id", base::Int64ToString(GetId()));
+  node_info->SetBoolean("isFolder", GetIsFolder());
+  node_info->SetString("title", GetTitle());
+  node_info->Set("type", ModelTypeToValue(GetModelType()));
+  return node_info;
+}
+
+DictionaryValue* BaseNode::GetDetailsAsValue() const {
+  DictionaryValue* node_info = GetSummaryAsValue();
+  // TODO(akalin): Return time in a better format.
+  node_info->SetString("modificationTime",
+                       base::Int64ToString(GetModificationTime()));
+  node_info->SetString("parentId", base::Int64ToString(GetParentId()));
+  // Specifics are already in the Entry value, so no need to duplicate
+  // it here.
+  node_info->SetString("externalId",
+                       base::Int64ToString(GetExternalId()));
+  node_info->SetString("predecessorId",
+                       base::Int64ToString(GetPredecessorId()));
+  node_info->SetString("successorId",
+                       base::Int64ToString(GetSuccessorId()));
+  node_info->SetString("firstChildId",
+                       base::Int64ToString(GetFirstChildId()));
+  node_info->Set("entry", GetEntry()->ToValue());
+  return node_info;
+}
+
+void BaseNode::GetFaviconBytes(std::vector<unsigned char>* output) const {
+  if (!output)
+    return;
+  const std::string& favicon = GetBookmarkSpecifics().favicon();
+  output->assign(reinterpret_cast<const unsigned char*>(favicon.data()),
+      reinterpret_cast<const unsigned char*>(favicon.data() +
+                                             favicon.length()));
+}
+
+int64 BaseNode::GetExternalId() const {
+  return GetEntry()->Get(syncable::LOCAL_EXTERNAL_ID);
+}
+
+const sync_pb::AppSpecifics& BaseNode::GetAppSpecifics() const {
+  DCHECK_EQ(syncable::APPS, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::app);
+}
+
+const sync_pb::AutofillSpecifics& BaseNode::GetAutofillSpecifics() const {
+  DCHECK_EQ(syncable::AUTOFILL, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::autofill);
+}
+
+const AutofillProfileSpecifics& BaseNode::GetAutofillProfileSpecifics() const {
+  DCHECK_EQ(GetModelType(), syncable::AUTOFILL_PROFILE);
+  return GetEntitySpecifics().GetExtension(sync_pb::autofill_profile);
+}
+
+const sync_pb::BookmarkSpecifics& BaseNode::GetBookmarkSpecifics() const {
+  DCHECK_EQ(syncable::BOOKMARKS, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::bookmark);
+}
+
+const sync_pb::NigoriSpecifics& BaseNode::GetNigoriSpecifics() const {
+  DCHECK_EQ(syncable::NIGORI, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::nigori);
+}
+
+const sync_pb::PasswordSpecificsData& BaseNode::GetPasswordSpecifics() const {
+  DCHECK_EQ(syncable::PASSWORDS, GetModelType());
+  return *password_data_;
+}
+
+const sync_pb::ThemeSpecifics& BaseNode::GetThemeSpecifics() const {
+  DCHECK_EQ(syncable::THEMES, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::theme);
+}
+
+const sync_pb::TypedUrlSpecifics& BaseNode::GetTypedUrlSpecifics() const {
+  DCHECK_EQ(syncable::TYPED_URLS, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::typed_url);
+}
+
+const sync_pb::ExtensionSpecifics& BaseNode::GetExtensionSpecifics() const {
+  DCHECK_EQ(syncable::EXTENSIONS, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::extension);
+}
+
+const sync_pb::SessionSpecifics& BaseNode::GetSessionSpecifics() const {
+  DCHECK_EQ(syncable::SESSIONS, GetModelType());
+  return GetEntitySpecifics().GetExtension(sync_pb::session);
+}
+
+const sync_pb::EntitySpecifics& BaseNode::GetEntitySpecifics() const {
+  return GetUnencryptedSpecifics(GetEntry());
+}
+
+syncable::ModelType BaseNode::GetModelType() const {
+  return GetEntry()->GetModelType();
+}
+
+void BaseNode::SetUnencryptedSpecifics(
+    const sync_pb::EntitySpecifics& specifics) {
+  syncable::ModelType type = syncable::GetModelTypeFromSpecifics(specifics);
+  DCHECK_NE(syncable::UNSPECIFIED, type);
+  if (GetModelType() != syncable::UNSPECIFIED) {
+    DCHECK_EQ(GetModelType(), type);
+  }
+  unencrypted_data_.CopyFrom(specifics);
+}
+
+}  // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/base_node.h b/chrome/browser/sync/internal_api/base_node.h
new file mode 100644
index 0000000..8759966
--- /dev/null
+++ b/chrome/browser/sync/internal_api/base_node.h
@@ -0,0 +1,224 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_BASE_NODE_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_BASE_NODE_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/sync/protocol/sync.pb.h"
+#include "chrome/browser/sync/syncable/model_type.h"
+#include "googleurl/src/gurl.h"
+
+// Forward declarations of internal class types so that sync API objects
+// may have opaque pointers to these types.
+namespace base {
+class DictionaryValue;
+}
+
+namespace syncable {
+class BaseTransaction;
+class Entry;
+}
+
+namespace sync_pb {
+class AppSpecifics;
+class AutofillSpecifics;
+class AutofillProfileSpecifics;
+class BookmarkSpecifics;
+class EntitySpecifics;
+class ExtensionSpecifics;
+class SessionSpecifics;
+class NigoriSpecifics;
+class PreferenceSpecifics;
+class PasswordSpecificsData;
+class ThemeSpecifics;
+class TypedUrlSpecifics;
+}
+
+namespace sync_api {
+
+class BaseTransaction;
+
+// A valid BaseNode will never have an ID of zero.
+static const int64 kInvalidId = 0;
+
+// BaseNode wraps syncable::Entry, and corresponds to a single object's state.
+// This, like syncable::Entry, is intended for use on the stack.  A valid
+// transaction is necessary to create a BaseNode or any of its children.
+// Unlike syncable::Entry, a sync API BaseNode is identified primarily by its
+// int64 metahandle, which we call an ID here.
+class BaseNode {
+ public:
+  // All subclasses of BaseNode must provide a way to initialize themselves by
+  // doing an ID lookup.  Returns false on failure.  An invalid or deleted
+  // ID will result in failure.
+  virtual bool InitByIdLookup(int64 id) = 0;
+
+  // All subclasses of BaseNode must also provide a way to initialize themselves
+  // by doing a client tag lookup. Returns false on failure. A deleted node
+  // will return FALSE.
+  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
+      const std::string& tag) = 0;
+
+  // Each object is identified by a 64-bit id (internally, the syncable
+  // metahandle).  These ids are strictly local handles.  They will persist
+  // on this client, but the same object on a different client may have a
+  // different ID value.
+  virtual int64 GetId() const;
+
+  // Returns the modification time of the object (in TimeTicks internal format).
+  int64 GetModificationTime() const;
+
+  // Nodes are hierarchically arranged into a single-rooted tree.
+  // InitByRootLookup on ReadNode allows access to the root. GetParentId is
+  // how you find a node's parent.
+  int64 GetParentId() const;
+
+  // Nodes are either folders or not.  This corresponds to the IS_DIR property
+  // of syncable::Entry.
+  bool GetIsFolder() const;
+
+  // Returns the title of the object.
+  // Uniqueness of the title is not enforced on siblings -- it is not an error
+  // for two children to share a title.
+  std::string GetTitle() const;
+
+  // Returns the model type of this object.  The model type is set at node
+  // creation time and is expected never to change.
+  syncable::ModelType GetModelType() const;
+
+  // Getter specific to the BOOKMARK datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == BOOKMARK.
+  const sync_pb::BookmarkSpecifics& GetBookmarkSpecifics() const;
+
+  // Legacy, bookmark-specific getter that wraps GetBookmarkSpecifics() above.
+  // Returns the URL of a bookmark object.
+  // TODO(ncarter): Remove this datatype-specific accessor.
+  GURL GetURL() const;
+
+  // Legacy, bookmark-specific getter that wraps GetBookmarkSpecifics() above.
+  // Fill in a vector with the byte data of this node's favicon.  Assumes
+  // that the node is a bookmark.
+  // Favicons are expected to be PNG images, and though no verification is
+  // done on the syncapi client of this, the server may reject favicon updates
+  // that are invalid for whatever reason.
+  // TODO(ncarter): Remove this datatype-specific accessor.
+  void GetFaviconBytes(std::vector<unsigned char>* output) const;
+
+  // Getter specific to the APPS datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == APPS.
+  const sync_pb::AppSpecifics& GetAppSpecifics() const;
+
+  // Getter specific to the AUTOFILL datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == AUTOFILL.
+  const sync_pb::AutofillSpecifics& GetAutofillSpecifics() const;
+
+  virtual const sync_pb::AutofillProfileSpecifics&
+      GetAutofillProfileSpecifics() const;
+
+  // Getter specific to the NIGORI datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == NIGORI.
+  const sync_pb::NigoriSpecifics& GetNigoriSpecifics() const;
+
+  // Getter specific to the PASSWORD datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == PASSWORD.
+  const sync_pb::PasswordSpecificsData& GetPasswordSpecifics() const;
+
+  // Getter specific to the PREFERENCE datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == PREFERENCE.
+  const sync_pb::PreferenceSpecifics& GetPreferenceSpecifics() const;
+
+  // Getter specific to the THEME datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == THEME.
+  const sync_pb::ThemeSpecifics& GetThemeSpecifics() const;
+
+  // Getter specific to the TYPED_URLS datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == TYPED_URLS.
+  const sync_pb::TypedUrlSpecifics& GetTypedUrlSpecifics() const;
+
+  // Getter specific to the EXTENSIONS datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == EXTENSIONS.
+  const sync_pb::ExtensionSpecifics& GetExtensionSpecifics() const;
+
+  // Getter specific to the SESSIONS datatype.  Returns protobuf
+  // data.  Can only be called if GetModelType() == SESSIONS.
+  const sync_pb::SessionSpecifics& GetSessionSpecifics() const;
+
+  const sync_pb::EntitySpecifics& GetEntitySpecifics() const;
+
+  // Returns the local external ID associated with the node.
+  int64 GetExternalId() const;
+
+  // Return the ID of the node immediately before this in the sibling order.
+  // For the first node in the ordering, return 0.
+  int64 GetPredecessorId() const;
+
+  // Return the ID of the node immediately after this in the sibling order.
+  // For the last node in the ordering, return 0.
+  virtual int64 GetSuccessorId() const;
+
+  // Return the ID of the first child of this node.  If this node has no
+  // children, return 0.
+  virtual int64 GetFirstChildId() const;
+
+  // These virtual accessors provide access to data members of derived classes.
+  virtual const syncable::Entry* GetEntry() const = 0;
+  virtual const BaseTransaction* GetTransaction() const = 0;
+
+  // Dumps a summary of node info into a DictionaryValue and returns it.
+  // Transfers ownership of the DictionaryValue to the caller.
+  base::DictionaryValue* GetSummaryAsValue() const;
+
+  // Dumps all node details into a DictionaryValue and returns it.
+  // Transfers ownership of the DictionaryValue to the caller.
+  base::DictionaryValue* GetDetailsAsValue() const;
+
+ protected:
+  BaseNode();
+  virtual ~BaseNode();
+  // The server has a size limit on client tags, so we generate a fixed length
+  // hash locally. This also ensures that ModelTypes have unique namespaces.
+  static std::string GenerateSyncableHash(syncable::ModelType model_type,
+      const std::string& client_tag);
+
+  // Determines whether part of the entry is encrypted, and if so attempts to
+  // decrypt it. Unless decryption is necessary and fails, this will always
+  // return |true|. If the contents are encrypted, the decrypted data will be
+  // stored in |unencrypted_data_|.
+  // This method is invoked once when the BaseNode is initialized.
+  bool DecryptIfNecessary();
+
+  // Returns the unencrypted specifics associated with |entry|. If |entry| was
+  // not encrypted, it directly returns |entry|'s EntitySpecifics. Otherwise,
+  // returns |unencrypted_data_|.
+  const sync_pb::EntitySpecifics& GetUnencryptedSpecifics(
+      const syncable::Entry* entry) const;
+
+  // Copy |specifics| into |unencrypted_data_|.
+  void SetUnencryptedSpecifics(const sync_pb::EntitySpecifics& specifics);
+
+ private:
+  void* operator new(size_t size);  // Node is meant for stack use only.
+
+  // A holder for the unencrypted data stored in an encrypted node.
+  sync_pb::EntitySpecifics unencrypted_data_;
+
+  // Same as |unencrypted_data_|, but for legacy password encryption.
+  scoped_ptr<sync_pb::PasswordSpecificsData> password_data_;
+
+  friend class SyncApiTest;
+  FRIEND_TEST_ALL_PREFIXES(SyncApiTest, GenerateSyncableHash);
+
+  DISALLOW_COPY_AND_ASSIGN(BaseNode);
+};
+
+}  // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_BASE_NODE_H_
diff --git a/chrome/browser/sync/internal_api/base_transaction.cc b/chrome/browser/sync/internal_api/base_transaction.cc
new file mode 100644
index 0000000..8d26702
--- /dev/null
+++ b/chrome/browser/sync/internal_api/base_transaction.cc
@@ -0,0 +1,35 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base_transaction.h"
+
+#include "chrome/browser/sync/syncable/directory_manager.h"
+#include "chrome/browser/sync/util/cryptographer.h"
+
+using browser_sync::Cryptographer;
+
+namespace sync_api {
+
+//////////////////////////////////////////////////////////////////////////
+// BaseTransaction member definitions
+BaseTransaction::BaseTransaction(UserShare* share)
+    : lookup_(NULL) {
+  DCHECK(share && share->dir_manager.get());
+  lookup_ = new syncable::ScopedDirLookup(share->dir_manager.get(),
+                                          share->name);
+  cryptographer_ = share->dir_manager->GetCryptographer(this);
+  if (!(lookup_->good()))
+    DCHECK(false) << "ScopedDirLookup failed on valid DirManager.";
+}
+BaseTransaction::~BaseTransaction() {
+  delete lookup_;
+}
+
+syncable::ModelTypeSet GetEncryptedTypes(
+    const sync_api::BaseTransaction* trans) {
+  Cryptographer* cryptographer = trans->GetCryptographer();
+  return cryptographer->GetEncryptedTypes();
+}
+
+} // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/base_transaction.h b/chrome/browser/sync/internal_api/base_transaction.h
new file mode 100644
index 0000000..9bf2fb3
--- /dev/null
+++ b/chrome/browser/sync/internal_api/base_transaction.h
@@ -0,0 +1,59 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_BASE_TRANSACTION_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_BASE_TRANSACTION_H_
+#pragma once
+
+#include "chrome/browser/sync/internal_api/user_share.h"
+
+#include "chrome/browser/sync/util/cryptographer.h"
+
+namespace syncable {
+class BaseTransaction;
+class ScopedDirLookup;
+}
+
+namespace sync_api {
+
+// Sync API's BaseTransaction, ReadTransaction, and WriteTransaction allow for
+// batching of several read and/or write operations.  The read and write
+// operations are performed by creating ReadNode and WriteNode instances using
+// the transaction. These transaction classes wrap identically named classes in
+// syncable, and are used in a similar way. Unlike syncable::BaseTransaction,
+// whose construction requires an explicit syncable::ScopedDirLookup, a sync
+// API BaseTransaction creates its own ScopedDirLookup implicitly.
+class BaseTransaction {
+ public:
+  // Provide access to the underlying syncable.h objects from BaseNode.
+  virtual syncable::BaseTransaction* GetWrappedTrans() const = 0;
+  const syncable::ScopedDirLookup& GetLookup() const { return *lookup_; }
+  browser_sync::Cryptographer* GetCryptographer() const {
+    return cryptographer_;
+  }
+
+ protected:
+  // The ScopedDirLookup is created in the constructor and destroyed
+  // in the destructor.  Creation of the ScopedDirLookup is not expected
+  // to fail.
+  explicit BaseTransaction(UserShare* share);
+  virtual ~BaseTransaction();
+
+  BaseTransaction() { lookup_= NULL; }
+
+ private:
+  // A syncable ScopedDirLookup, which is the parent of syncable transactions.
+  syncable::ScopedDirLookup* lookup_;
+
+  browser_sync::Cryptographer* cryptographer_;
+
+  DISALLOW_COPY_AND_ASSIGN(BaseTransaction);
+};
+
+syncable::ModelTypeSet GetEncryptedTypes(
+    const sync_api::BaseTransaction* trans);
+
+}  // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_BASE_TRANSACTION_H_
diff --git a/chrome/browser/sync/internal_api/read_node.cc b/chrome/browser/sync/internal_api/read_node.cc
new file mode 100644
index 0000000..73e0b29
--- /dev/null
+++ b/chrome/browser/sync/internal_api/read_node.cc
@@ -0,0 +1,92 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/internal_api/read_node.h"
+
+#include "base/logging.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/syncable/syncable.h"
+
+namespace sync_api {
+
+//////////////////////////////////////////////////////////////////////////
+// ReadNode member definitions
+ReadNode::ReadNode(const BaseTransaction* transaction)
+    : entry_(NULL), transaction_(transaction) {
+  DCHECK(transaction);
+}
+
+ReadNode::ReadNode() {
+  entry_ = NULL;
+  transaction_ = NULL;
+}
+
+ReadNode::~ReadNode() {
+  delete entry_;
+}
+
+void ReadNode::InitByRootLookup() {
+  DCHECK(!entry_) << "Init called twice";
+  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
+  entry_ = new syncable::Entry(trans, syncable::GET_BY_ID, trans->root_id());
+  if (!entry_->good())
+    DCHECK(false) << "Could not lookup root node for reading.";
+}
+
+bool ReadNode::InitByIdLookup(int64 id) {
+  DCHECK(!entry_) << "Init called twice";
+  DCHECK_NE(id, kInvalidId);
+  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
+  entry_ = new syncable::Entry(trans, syncable::GET_BY_HANDLE, id);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  LOG_IF(WARNING, model_type == syncable::UNSPECIFIED ||
+                  model_type == syncable::TOP_LEVEL_FOLDER)
+      << "SyncAPI InitByIdLookup referencing unusual object.";
+  return DecryptIfNecessary();
+}
+
+bool ReadNode::InitByClientTagLookup(syncable::ModelType model_type,
+                                     const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+
+  const std::string hash = GenerateSyncableHash(model_type, tag);
+
+  entry_ = new syncable::Entry(transaction_->GetWrappedTrans(),
+                               syncable::GET_BY_CLIENT_TAG, hash);
+  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
+          DecryptIfNecessary());
+}
+
+const syncable::Entry* ReadNode::GetEntry() const {
+  return entry_;
+}
+
+const BaseTransaction* ReadNode::GetTransaction() const {
+  return transaction_;
+}
+
+bool ReadNode::InitByTagLookup(const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
+  entry_ = new syncable::Entry(trans, syncable::GET_BY_SERVER_TAG, tag);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  LOG_IF(WARNING, model_type == syncable::UNSPECIFIED ||
+                  model_type == syncable::TOP_LEVEL_FOLDER)
+      << "SyncAPI InitByTagLookup referencing unusually typed object.";
+  return DecryptIfNecessary();
+}
+
+}  // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/read_node.h b/chrome/browser/sync/internal_api/read_node.h
new file mode 100644
index 0000000..9ad9715
--- /dev/null
+++ b/chrome/browser/sync/internal_api/read_node.h
@@ -0,0 +1,79 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_READ_NODE_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_READ_NODE_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "chrome/browser/sync/internal_api/base_node.h"
+#include "chrome/browser/sync/syncable/model_type.h"
+
+namespace sync_pb {
+class AppSpecifics;
+class AutofillSpecifics;
+class AutofillProfileSpecifics;
+class BookmarkSpecifics;
+class EntitySpecifics;
+class ExtensionSpecifics;
+class SessionSpecifics;
+class NigoriSpecifics;
+class PreferenceSpecifics;
+class PasswordSpecificsData;
+class ThemeSpecifics;
+class TypedUrlSpecifics;
+}
+
+namespace sync_api {
+
+// ReadNode wraps a syncable::Entry to provide the functionality of a
+// read-only BaseNode.
+class ReadNode : public BaseNode {
+ public:
+  // Create an unpopulated ReadNode on the given transaction.  Call some flavor
+  // of Init to populate the ReadNode with a database entry.
+  explicit ReadNode(const BaseTransaction* transaction);
+  virtual ~ReadNode();
+
+  // A client must use one (and only one) of the following Init variants to
+  // populate the node.
+
+  // BaseNode implementation.
+  virtual bool InitByIdLookup(int64 id);
+  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
+      const std::string& tag);
+
+  // There is always a root node, so this can't fail.  The root node is
+  // never mutable, so root lookup is only possible on a ReadNode.
+  void InitByRootLookup();
+
+  // Each server-created permanent node is tagged with a unique string.
+  // Look up the node with the particular tag.  If it does not exist,
+  // return false.
+  bool InitByTagLookup(const std::string& tag);
+
+  // Implementation of BaseNode's abstract virtual accessors.
+  virtual const syncable::Entry* GetEntry() const;
+  virtual const BaseTransaction* GetTransaction() const;
+
+ protected:
+  ReadNode();
+
+ private:
+  void* operator new(size_t size);  // Node is meant for stack use only.
+
+  // The underlying syncable object which this class wraps.
+  syncable::Entry* entry_;
+
+  // The sync API transaction that is the parent of this node.
+  const BaseTransaction* transaction_;
+
+  DISALLOW_COPY_AND_ASSIGN(ReadNode);
+};
+
+}  // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_READ_NODE_H_
diff --git a/chrome/browser/sync/engine/read_node_mock.cc b/chrome/browser/sync/internal_api/read_node_mock.cc
index 6916688..64007b5 100644
--- a/chrome/browser/sync/engine/read_node_mock.cc
+++ b/chrome/browser/sync/internal_api/read_node_mock.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/sync/engine/read_node_mock.h"
+#include "chrome/browser/sync/internal_api/read_node_mock.h"
 
 #include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
 
diff --git a/chrome/browser/sync/engine/read_node_mock.h b/chrome/browser/sync/internal_api/read_node_mock.h
index 9d31f6f..598d4e2 100644
--- a/chrome/browser/sync/engine/read_node_mock.h
+++ b/chrome/browser/sync/internal_api/read_node_mock.h
@@ -2,13 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be

 // found in the LICENSE file.

 

-#ifndef CHROME_BROWSER_SYNC_ENGINE_READ_NODE_MOCK_H_

-#define CHROME_BROWSER_SYNC_ENGINE_READ_NODE_MOCK_H_

+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_READ_NODE_MOCK_H_

+#define CHROME_BROWSER_SYNC_INTERNAL_API_READ_NODE_MOCK_H_

 #pragma once

 

 #include <string>

 

-#include "chrome/browser/sync/engine/syncapi.h"

+#include "chrome/browser/sync/internal_api/read_node.h"

 #include "testing/gmock/include/gmock/gmock.h"

 

 class ReadNodeMock : public sync_api::ReadNode {

@@ -27,5 +27,4 @@ class ReadNodeMock : public sync_api::ReadNode {
   MOCK_METHOD1(InitByIdLookup, bool(int64 id));

 };

 

-#endif  // CHROME_BROWSER_SYNC_ENGINE_READ_NODE_MOCK_H_

-

+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_READ_NODE_MOCK_H_

diff --git a/chrome/browser/sync/internal_api/read_transaction.cc b/chrome/browser/sync/internal_api/read_transaction.cc
new file mode 100644
index 0000000..40691dd
--- /dev/null
+++ b/chrome/browser/sync/internal_api/read_transaction.cc
@@ -0,0 +1,37 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+
+#include "chrome/browser/sync/syncable/syncable.h"
+
+namespace sync_api {
+
+//////////////////////////////////////////////////////////////////////////
+// ReadTransaction member definitions
+ReadTransaction::ReadTransaction(const tracked_objects::Location& from_here,
+                                 UserShare* share)
+    : BaseTransaction(share),
+      transaction_(NULL),
+      close_transaction_(true) {
+  transaction_ = new syncable::ReadTransaction(from_here, GetLookup());
+}
+
+ReadTransaction::ReadTransaction(UserShare* share,
+                                 syncable::BaseTransaction* trans)
+    : BaseTransaction(share),
+      transaction_(trans),
+      close_transaction_(false) {}
+
+ReadTransaction::~ReadTransaction() {
+  if (close_transaction_) {
+    delete transaction_;
+  }
+}
+
+syncable::BaseTransaction* ReadTransaction::GetWrappedTrans() const {
+  return transaction_;
+}
+
+} // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/read_transaction.h b/chrome/browser/sync/internal_api/read_transaction.h
new file mode 100644
index 0000000..c1b97d9
--- /dev/null
+++ b/chrome/browser/sync/internal_api/read_transaction.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_READ_TRANSACTION_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_READ_TRANSACTION_H_
+
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+
+namespace tracked_objects {
+class Location;
+}  // namespace tracked_objects
+
+namespace sync_api {
+
+struct UserShare;
+
+// Sync API's ReadTransaction is a read-only BaseTransaction.  It wraps
+// a syncable::ReadTransaction.
+class ReadTransaction : public BaseTransaction {
+ public:
+  // Start a new read-only transaction on the specified repository.
+  ReadTransaction(const tracked_objects::Location& from_here,
+                  UserShare* share);
+
+  // Resume the middle of a transaction. Will not close transaction.
+  ReadTransaction(UserShare* share, syncable::BaseTransaction* trans);
+
+  virtual ~ReadTransaction();
+
+  // BaseTransaction override.
+  virtual syncable::BaseTransaction* GetWrappedTrans() const;
+ private:
+  void* operator new(size_t size);  // Transaction is meant for stack use only.
+
+  // The underlying syncable object which this class wraps.
+  syncable::BaseTransaction* transaction_;
+  bool close_transaction_;
+
+  DISALLOW_COPY_AND_ASSIGN(ReadTransaction);
+};
+
+} // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_READ_TRANSACTION_H_
diff --git a/chrome/browser/sync/engine/syncapi.cc b/chrome/browser/sync/internal_api/sync_manager.cc
index 408f71c..40ebdd5 100644
--- a/chrome/browser/sync/engine/syncapi.cc
+++ b/chrome/browser/sync/internal_api/sync_manager.cc
@@ -2,47 +2,29 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/sync/engine/syncapi.h"
-
-#include <algorithm>
-#include <bitset>
-#include <iomanip>
-#include <list>
-#include <map>
-#include <queue>
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+
 #include <string>
 #include <vector>
 
 #include "base/base64.h"
-#include "base/bind.h"
-#include "base/callback.h"
-#include "base/command_line.h"
-#include "base/compiler_specific.h"
 #include "base/json/json_writer.h"
-#include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
-#include "base/message_loop.h"
-#include "base/observer_list.h"
-#include "base/sha1.h"
 #include "base/string_number_conversions.h"
-#include "base/string_util.h"
-#include "base/threading/thread_checker.h"
-#include "base/time.h"
-#include "base/tracked.h"
-#include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/sync/engine/all_status.h"
 #include "chrome/browser/sync/engine/change_reorder_buffer.h"
-#include "chrome/browser/sync/engine/http_post_provider_factory.h"
-#include "chrome/browser/sync/engine/model_safe_worker.h"
-#include "chrome/browser/sync/engine/nigori_util.h"
-#include "chrome/browser/sync/engine/nudge_source.h"
 #include "chrome/browser/sync/engine/net/server_connection_manager.h"
 #include "chrome/browser/sync/engine/net/syncapi_server_connection_manager.h"
-#include "chrome/browser/sync/engine/nudge_source.h"
+#include "chrome/browser/sync/engine/nigori_util.h"
+#include "chrome/browser/sync/engine/syncapi_internal.h"
+#include "chrome/browser/sync/engine/syncer_types.h"
 #include "chrome/browser/sync/engine/sync_scheduler.h"
-#include "chrome/browser/sync/engine/syncer.h"
+#include "chrome/browser/sync/internal_api/base_node.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/user_share.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/js/js_arg_list.h"
 #include "chrome/browser/sync/js/js_backend.h"
 #include "chrome/browser/sync/js/js_event_details.h"
@@ -52,29 +34,18 @@
 #include "chrome/browser/sync/js/js_transaction_observer.h"
 #include "chrome/browser/sync/notifier/sync_notifier.h"
 #include "chrome/browser/sync/notifier/sync_notifier_observer.h"
-#include "chrome/browser/sync/protocol/app_specifics.pb.h"
-#include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
-#include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
-#include "chrome/browser/sync/protocol/extension_specifics.pb.h"
-#include "chrome/browser/sync/protocol/nigori_specifics.pb.h"
-#include "chrome/browser/sync/protocol/preference_specifics.pb.h"
 #include "chrome/browser/sync/protocol/proto_value_conversions.h"
-#include "chrome/browser/sync/protocol/service_constants.h"
-#include "chrome/browser/sync/protocol/session_specifics.pb.h"
-#include "chrome/browser/sync/protocol/sync.pb.h"
-#include "chrome/browser/sync/protocol/theme_specifics.pb.h"
-#include "chrome/browser/sync/protocol/typed_url_specifics.pb.h"
-#include "chrome/browser/sync/sessions/sync_session.h"
-#include "chrome/browser/sync/sessions/sync_session_context.h"
 #include "chrome/browser/sync/syncable/directory_change_delegate.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/browser/sync/syncable/model_type.h"
-#include "chrome/browser/sync/syncable/model_type_payload_map.h"
 #include "chrome/browser/sync/syncable/syncable.h"
+#include "chrome/browser/sync/util/cryptographer.h"
 #include "chrome/browser/sync/weak_handle.h"
-#include "chrome/common/chrome_switches.h"
 #include "net/base/network_change_notifier.h"
 
+using std::string;
+using std::vector;
+
 using base::TimeDelta;
 using browser_sync::AllStatus;
 using browser_sync::Cryptographer;
@@ -82,1061 +53,42 @@ using browser_sync::JsArgList;
 using browser_sync::JsBackend;
 using browser_sync::JsEventDetails;
 using browser_sync::JsEventHandler;
+using browser_sync::JsEventHandler;
 using browser_sync::JsReplyHandler;
 using browser_sync::JsSyncManagerObserver;
 using browser_sync::JsTransactionObserver;
-using browser_sync::MakeWeakHandle;
-using browser_sync::WeakHandle;
+using browser_sync::ModelSafeWorkerRegistrar;
+using browser_sync::kNigoriTag;
 using browser_sync::KeyParams;
 using browser_sync::ModelSafeRoutingInfo;
-using browser_sync::ModelSafeWorker;
-using browser_sync::ModelSafeWorkerRegistrar;
 using browser_sync::ServerConnectionEvent;
 using browser_sync::ServerConnectionEventListener;
 using browser_sync::SyncEngineEvent;
 using browser_sync::SyncEngineEventListener;
-using browser_sync::Syncer;
 using browser_sync::SyncScheduler;
-using browser_sync::kNigoriTag;
+using browser_sync::Syncer;
+using browser_sync::WeakHandle;
 using browser_sync::sessions::SyncSessionContext;
-using std::list;
-using std::hex;
-using std::string;
-using std::vector;
-using syncable::Directory;
 using syncable::DirectoryManager;
-using syncable::Entry;
 using syncable::EntryKernelMutationSet;
-using syncable::kEncryptedString;
 using syncable::ModelType;
 using syncable::ModelTypeBitSet;
-using syncable::WriterTag;
 using syncable::SPECIFICS;
-using sync_pb::AutofillProfileSpecifics;
-
-namespace {
 
 typedef GoogleServiceAuthError AuthError;
 
-static const int kThreadExitTimeoutMsec = 60000;
-static const int kSSLPort = 443;
+namespace {
+
 static const int kSyncSchedulerDelayMsec = 250;
 
 #if defined(OS_CHROMEOS)
 static const int kChromeOSNetworkChangeReactionDelayHackMsec = 5000;
 #endif  // OS_CHROMEOS
 
-}  // namespace
+} // namespace
 
 namespace sync_api {
 
-static const FilePath::CharType kBookmarkSyncUserSettingsDatabase[] =
-    FILE_PATH_LITERAL("BookmarkSyncSettings.sqlite3");
-static const char kDefaultNameForNewNodes[] = " ";
-
-// The list of names which are reserved for use by the server.
-static const char* kForbiddenServerNames[] = { "", ".", ".." };
-
-//////////////////////////////////////////////////////////////////////////
-// Static helper functions.
-
-// Helper function to look up the int64 metahandle of an object given the ID
-// string.
-static int64 IdToMetahandle(syncable::BaseTransaction* trans,
-                            const syncable::Id& id) {
-  syncable::Entry entry(trans, syncable::GET_BY_ID, id);
-  if (!entry.good())
-    return kInvalidId;
-  return entry.Get(syncable::META_HANDLE);
-}
-
-// Checks whether |name| is a server-illegal name followed by zero or more space
-// characters.  The three server-illegal names are the empty string, dot, and
-// dot-dot.  Very long names (>255 bytes in UTF-8 Normalization Form C) are
-// also illegal, but are not considered here.
-static bool IsNameServerIllegalAfterTrimming(const std::string& name) {
-  size_t untrimmed_count = name.find_last_not_of(' ') + 1;
-  for (size_t i = 0; i < arraysize(kForbiddenServerNames); ++i) {
-    if (name.compare(0, untrimmed_count, kForbiddenServerNames[i]) == 0)
-      return true;
-  }
-  return false;
-}
-
-static bool EndsWithSpace(const std::string& string) {
-  return !string.empty() && *string.rbegin() == ' ';
-}
-
-// When taking a name from the syncapi, append a space if it matches the
-// pattern of a server-illegal name followed by zero or more spaces.
-static void SyncAPINameToServerName(const std::wstring& sync_api_name,
-                                    std::string* out) {
-  *out = WideToUTF8(sync_api_name);
-  if (IsNameServerIllegalAfterTrimming(*out))
-    out->append(" ");
-}
-
-// In the reverse direction, if a server name matches the pattern of a
-// server-illegal name followed by one or more spaces, remove the trailing
-// space.
-static void ServerNameToSyncAPIName(const std::string& server_name,
-                                    std::string* out) {
-  CHECK(out);
-  int length_to_copy = server_name.length();
-  if (IsNameServerIllegalAfterTrimming(server_name) &&
-      EndsWithSpace(server_name)) {
-    --length_to_copy;
-  }
-  *out = std::string(server_name.c_str(), length_to_copy);
-}
-
-// Compare the values of two EntitySpecifics, accounting for encryption.
-static bool AreSpecificsEqual(const browser_sync::Cryptographer* cryptographer,
-                              const sync_pb::EntitySpecifics& left,
-                              const sync_pb::EntitySpecifics& right) {
-  // Note that we can't compare encrypted strings directly as they are seeded
-  // with a random value.
-  std::string left_plaintext, right_plaintext;
-  if (left.has_encrypted()) {
-    if (!cryptographer->CanDecrypt(left.encrypted())) {
-      NOTREACHED() << "Attempting to compare undecryptable data.";
-      return false;
-    }
-    left_plaintext = cryptographer->DecryptToString(left.encrypted());
-  } else {
-    left_plaintext = left.SerializeAsString();
-  }
-  if (right.has_encrypted()) {
-    if (!cryptographer->CanDecrypt(right.encrypted())) {
-      NOTREACHED() << "Attempting to compare undecryptable data.";
-      return false;
-    }
-    right_plaintext = cryptographer->DecryptToString(right.encrypted());
-  } else {
-    right_plaintext = right.SerializeAsString();
-  }
-  if (left_plaintext == right_plaintext) {
-    return true;
-  }
-  return false;
-}
-
-// Helper function that converts a PassphraseRequiredReason value to a string.
-std::string PassphraseRequiredReasonToString(
-    PassphraseRequiredReason reason) {
-  switch (reason) {
-    case REASON_PASSPHRASE_NOT_REQUIRED:
-      return "REASON_PASSPHRASE_NOT_REQUIRED";
-    case REASON_ENCRYPTION:
-      return "REASON_ENCRYPTION";
-    case REASON_DECRYPTION:
-      return "REASON_DECRYPTION";
-    case REASON_SET_PASSPHRASE_FAILED:
-      return "REASON_SET_PASSPHRASE_FAILED";
-    default:
-      NOTREACHED();
-      return "INVALID_REASON";
-  }
-}
-
-// Helper function to determine if initial sync had ended for types.
-bool InitialSyncEndedForTypes(syncable::ModelTypeSet types,
-                              sync_api::UserShare* share) {
-  syncable::ScopedDirLookup lookup(share->dir_manager.get(),
-                                   share->name);
-  if (!lookup.good()) {
-    DCHECK(false) << "ScopedDirLookup failed when checking initial sync";
-    return false;
-  }
-
-  for (syncable::ModelTypeSet::const_iterator i = types.begin();
-       i != types.end(); ++i) {
-    if (!lookup->initial_sync_ended_for_type(*i))
-      return false;
-  }
-  return true;
-}
-
-
-UserShare::UserShare() {}
-
-UserShare::~UserShare() {}
-
-////////////////////////////////////
-// BaseNode member definitions.
-
-BaseNode::BaseNode() : password_data_(new sync_pb::PasswordSpecificsData) {}
-
-BaseNode::~BaseNode() {}
-
-std::string BaseNode::GenerateSyncableHash(
-    syncable::ModelType model_type, const std::string& client_tag) {
-  // blank PB with just the extension in it has termination symbol,
-  // handy for delimiter
-  sync_pb::EntitySpecifics serialized_type;
-  syncable::AddDefaultExtensionValue(model_type, &serialized_type);
-  std::string hash_input;
-  serialized_type.AppendToString(&hash_input);
-  hash_input.append(client_tag);
-
-  std::string encode_output;
-  CHECK(base::Base64Encode(base::SHA1HashString(hash_input), &encode_output));
-  return encode_output;
-}
-
-sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
-    const sync_pb::EntitySpecifics& specifics, Cryptographer* crypto) {
-  if (!specifics.HasExtension(sync_pb::password))
-    return NULL;
-  const sync_pb::PasswordSpecifics& password_specifics =
-      specifics.GetExtension(sync_pb::password);
-  if (!password_specifics.has_encrypted())
-    return NULL;
-  const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();
-  scoped_ptr<sync_pb::PasswordSpecificsData> data(
-      new sync_pb::PasswordSpecificsData);
-  if (!crypto->Decrypt(encrypted, data.get()))
-    return NULL;
-  return data.release();
-}
-
-bool BaseNode::DecryptIfNecessary() {
-  if (!GetEntry()->Get(syncable::UNIQUE_SERVER_TAG).empty())
-      return true;  // Ignore unique folders.
-  const sync_pb::EntitySpecifics& specifics =
-      GetEntry()->Get(syncable::SPECIFICS);
-  if (specifics.HasExtension(sync_pb::password)) {
-    // Passwords have their own legacy encryption structure.
-    scoped_ptr<sync_pb::PasswordSpecificsData> data(DecryptPasswordSpecifics(
-        specifics, GetTransaction()->GetCryptographer()));
-    if (!data.get()) {
-      LOG(ERROR) << "Failed to decrypt password specifics.";
-      return false;
-    }
-    password_data_.swap(data);
-    return true;
-  }
-
-  // We assume any node with the encrypted field set has encrypted data.
-  if (!specifics.has_encrypted())
-    return true;
-
-  const sync_pb::EncryptedData& encrypted =
-      specifics.encrypted();
-  std::string plaintext_data = GetTransaction()->GetCryptographer()->
-      DecryptToString(encrypted);
-  if (plaintext_data.length() == 0 ||
-      !unencrypted_data_.ParseFromString(plaintext_data)) {
-    LOG(ERROR) << "Failed to decrypt encrypted node of type " <<
-      syncable::ModelTypeToString(GetModelType()) << ".";
-    return false;
-  }
-  VLOG(2) << "Decrypted specifics of type "
-          << syncable::ModelTypeToString(GetModelType())
-          << " with content: " << plaintext_data;
-  return true;
-}
-
-const sync_pb::EntitySpecifics& BaseNode::GetUnencryptedSpecifics(
-    const syncable::Entry* entry) const {
-  const sync_pb::EntitySpecifics& specifics = entry->Get(SPECIFICS);
-  if (specifics.has_encrypted()) {
-    DCHECK(syncable::GetModelTypeFromSpecifics(unencrypted_data_) !=
-           syncable::UNSPECIFIED);
-    return unencrypted_data_;
-  } else {
-    DCHECK(syncable::GetModelTypeFromSpecifics(unencrypted_data_) ==
-           syncable::UNSPECIFIED);
-    return specifics;
-  }
-}
-
-int64 BaseNode::GetParentId() const {
-  return IdToMetahandle(GetTransaction()->GetWrappedTrans(),
-                        GetEntry()->Get(syncable::PARENT_ID));
-}
-
-int64 BaseNode::GetId() const {
-  return GetEntry()->Get(syncable::META_HANDLE);
-}
-
-int64 BaseNode::GetModificationTime() const {
-  return GetEntry()->Get(syncable::MTIME);
-}
-
-bool BaseNode::GetIsFolder() const {
-  return GetEntry()->Get(syncable::IS_DIR);
-}
-
-std::string BaseNode::GetTitle() const {
-  std::string result;
-  // TODO(zea): refactor bookmarks to not need this functionality.
-  if (syncable::BOOKMARKS == GetModelType() &&
-      GetEntry()->Get(syncable::SPECIFICS).has_encrypted()) {
-    // Special case for legacy bookmarks dealing with encryption.
-    ServerNameToSyncAPIName(GetBookmarkSpecifics().title(), &result);
-  } else {
-    ServerNameToSyncAPIName(GetEntry()->Get(syncable::NON_UNIQUE_NAME),
-                            &result);
-  }
-  return result;
-}
-
-GURL BaseNode::GetURL() const {
-  return GURL(GetBookmarkSpecifics().url());
-}
-
-int64 BaseNode::GetPredecessorId() const {
-  syncable::Id id_string = GetEntry()->Get(syncable::PREV_ID);
-  if (id_string.IsRoot())
-    return kInvalidId;
-  return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
-}
-
-int64 BaseNode::GetSuccessorId() const {
-  syncable::Id id_string = GetEntry()->Get(syncable::NEXT_ID);
-  if (id_string.IsRoot())
-    return kInvalidId;
-  return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
-}
-
-int64 BaseNode::GetFirstChildId() const {
-  syncable::Directory* dir = GetTransaction()->GetLookup();
-  syncable::BaseTransaction* trans = GetTransaction()->GetWrappedTrans();
-  syncable::Id id_string =
-      dir->GetFirstChildId(trans, GetEntry()->Get(syncable::ID));
-  if (id_string.IsRoot())
-    return kInvalidId;
-  return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
-}
-
-DictionaryValue* BaseNode::GetSummaryAsValue() const {
-  DictionaryValue* node_info = new DictionaryValue();
-  node_info->SetString("id", base::Int64ToString(GetId()));
-  node_info->SetBoolean("isFolder", GetIsFolder());
-  node_info->SetString("title", GetTitle());
-  node_info->Set("type", ModelTypeToValue(GetModelType()));
-  return node_info;
-}
-
-DictionaryValue* BaseNode::GetDetailsAsValue() const {
-  DictionaryValue* node_info = GetSummaryAsValue();
-  // TODO(akalin): Return time in a better format.
-  node_info->SetString("modificationTime",
-                       base::Int64ToString(GetModificationTime()));
-  node_info->SetString("parentId", base::Int64ToString(GetParentId()));
-  // Specifics are already in the Entry value, so no need to duplicate
-  // it here.
-  node_info->SetString("externalId",
-                       base::Int64ToString(GetExternalId()));
-  node_info->SetString("predecessorId",
-                       base::Int64ToString(GetPredecessorId()));
-  node_info->SetString("successorId",
-                       base::Int64ToString(GetSuccessorId()));
-  node_info->SetString("firstChildId",
-                       base::Int64ToString(GetFirstChildId()));
-  node_info->Set("entry", GetEntry()->ToValue());
-  return node_info;
-}
-
-void BaseNode::GetFaviconBytes(std::vector<unsigned char>* output) const {
-  if (!output)
-    return;
-  const std::string& favicon = GetBookmarkSpecifics().favicon();
-  output->assign(reinterpret_cast<const unsigned char*>(favicon.data()),
-      reinterpret_cast<const unsigned char*>(favicon.data() +
-                                             favicon.length()));
-}
-
-int64 BaseNode::GetExternalId() const {
-  return GetEntry()->Get(syncable::LOCAL_EXTERNAL_ID);
-}
-
-const sync_pb::AppSpecifics& BaseNode::GetAppSpecifics() const {
-  DCHECK_EQ(syncable::APPS, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::app);
-}
-
-const sync_pb::AutofillSpecifics& BaseNode::GetAutofillSpecifics() const {
-  DCHECK_EQ(syncable::AUTOFILL, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::autofill);
-}
-
-const AutofillProfileSpecifics& BaseNode::GetAutofillProfileSpecifics() const {
-  DCHECK_EQ(GetModelType(), syncable::AUTOFILL_PROFILE);
-  return GetEntitySpecifics().GetExtension(sync_pb::autofill_profile);
-}
-
-const sync_pb::BookmarkSpecifics& BaseNode::GetBookmarkSpecifics() const {
-  DCHECK_EQ(syncable::BOOKMARKS, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::bookmark);
-}
-
-const sync_pb::NigoriSpecifics& BaseNode::GetNigoriSpecifics() const {
-  DCHECK_EQ(syncable::NIGORI, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::nigori);
-}
-
-const sync_pb::PasswordSpecificsData& BaseNode::GetPasswordSpecifics() const {
-  DCHECK_EQ(syncable::PASSWORDS, GetModelType());
-  return *password_data_;
-}
-
-const sync_pb::ThemeSpecifics& BaseNode::GetThemeSpecifics() const {
-  DCHECK_EQ(syncable::THEMES, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::theme);
-}
-
-const sync_pb::TypedUrlSpecifics& BaseNode::GetTypedUrlSpecifics() const {
-  DCHECK_EQ(syncable::TYPED_URLS, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::typed_url);
-}
-
-const sync_pb::ExtensionSpecifics& BaseNode::GetExtensionSpecifics() const {
-  DCHECK_EQ(syncable::EXTENSIONS, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::extension);
-}
-
-const sync_pb::SessionSpecifics& BaseNode::GetSessionSpecifics() const {
-  DCHECK_EQ(syncable::SESSIONS, GetModelType());
-  return GetEntitySpecifics().GetExtension(sync_pb::session);
-}
-
-const sync_pb::EntitySpecifics& BaseNode::GetEntitySpecifics() const {
-  return GetUnencryptedSpecifics(GetEntry());
-}
-
-syncable::ModelType BaseNode::GetModelType() const {
-  return GetEntry()->GetModelType();
-}
-
-void BaseNode::SetUnencryptedSpecifics(
-    const sync_pb::EntitySpecifics& specifics) {
-  syncable::ModelType type = syncable::GetModelTypeFromSpecifics(specifics);
-  DCHECK_NE(syncable::UNSPECIFIED, type);
-  if (GetModelType() != syncable::UNSPECIFIED) {
-    DCHECK_EQ(GetModelType(), type);
-  }
-  unencrypted_data_.CopyFrom(specifics);
-}
-
-////////////////////////////////////
-// WriteNode member definitions
-// Static.
-bool WriteNode::UpdateEntryWithEncryption(
-    browser_sync::Cryptographer* cryptographer,
-    const sync_pb::EntitySpecifics& new_specifics,
-    syncable::MutableEntry* entry) {
-  syncable::ModelType type = syncable::GetModelTypeFromSpecifics(new_specifics);
-  DCHECK_GE(type, syncable::FIRST_REAL_MODEL_TYPE);
-  syncable::ModelTypeSet encrypted_types = cryptographer->GetEncryptedTypes();
-
-  sync_pb::EntitySpecifics generated_specifics;
-  if (type == syncable::PASSWORDS ||        // Has own encryption scheme.
-      type == syncable::NIGORI ||           // Encrypted separately.
-      encrypted_types.count(type) == 0 ||
-      new_specifics.has_encrypted()) {
-    // No encryption required.
-    generated_specifics.CopyFrom(new_specifics);
-  } else {
-    // Encrypt new_specifics into generated_specifics.
-    if (VLOG_IS_ON(2)) {
-      scoped_ptr<DictionaryValue> value(entry->ToValue());
-      std::string info;
-      base::JSONWriter::Write(value.get(), true, &info);
-      VLOG(2) << "Encrypting specifics of type "
-              << syncable::ModelTypeToString(type)
-              << " with content: "
-              << info;
-    }
-    if (!cryptographer->is_initialized())
-      return false;
-    syncable::AddDefaultExtensionValue(type, &generated_specifics);
-    if (!cryptographer->Encrypt(new_specifics,
-                                generated_specifics.mutable_encrypted())) {
-      NOTREACHED() << "Could not encrypt data for node of type "
-                   << syncable::ModelTypeToString(type);
-      return false;
-    }
-  }
-
-  const sync_pb::EntitySpecifics& old_specifics = entry->Get(SPECIFICS);
-  if (AreSpecificsEqual(cryptographer, old_specifics, generated_specifics)) {
-    // Even if the data is the same but the old specifics are encrypted with an
-    // old key, we should go ahead and re-encrypt with the new key.
-    if ((!old_specifics.has_encrypted() &&
-         !generated_specifics.has_encrypted()) ||
-         cryptographer->CanDecryptUsingDefaultKey(old_specifics.encrypted())) {
-      VLOG(2) << "Specifics of type " << syncable::ModelTypeToString(type)
-              << " already match, dropping change.";
-      return true;
-    }
-    // TODO(zea): Add some way to keep track of how often we're reencrypting
-    // because of a passphrase change.
-  }
-
-  if (generated_specifics.has_encrypted()) {
-    // Overwrite the possibly sensitive non-specifics data.
-    entry->Put(syncable::NON_UNIQUE_NAME, kEncryptedString);
-    // For bookmarks we actually put bogus data into the unencrypted specifics,
-    // else the server will try to do it for us.
-    if (type == syncable::BOOKMARKS) {
-      sync_pb::BookmarkSpecifics* bookmark_specifics =
-          generated_specifics.MutableExtension(sync_pb::bookmark);
-      if (!entry->Get(syncable::IS_DIR))
-        bookmark_specifics->set_url(kEncryptedString);
-      bookmark_specifics->set_title(kEncryptedString);
-    }
-  }
-  entry->Put(syncable::SPECIFICS, generated_specifics);
-  syncable::MarkForSyncing(entry);
-  return true;
-}
-
-void WriteNode::SetIsFolder(bool folder) {
-  if (entry_->Get(syncable::IS_DIR) == folder)
-    return;  // Skip redundant changes.
-
-  entry_->Put(syncable::IS_DIR, folder);
-  MarkForSyncing();
-}
-
-void WriteNode::SetTitle(const std::wstring& title) {
-  std::string server_legal_name;
-  SyncAPINameToServerName(title, &server_legal_name);
-
-  string old_name = entry_->Get(syncable::NON_UNIQUE_NAME);
-
-  if (server_legal_name == old_name)
-    return;  // Skip redundant changes.
-
-  // Only set NON_UNIQUE_NAME to the title if we're not encrypted.
-  if (GetEntitySpecifics().has_encrypted())
-    entry_->Put(syncable::NON_UNIQUE_NAME, kEncryptedString);
-  else
-    entry_->Put(syncable::NON_UNIQUE_NAME, server_legal_name);
-
-  // For bookmarks, we also set the title field in the specifics.
-  // TODO(zea): refactor bookmarks to not need this functionality.
-  if (GetModelType() == syncable::BOOKMARKS) {
-    sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
-    new_value.set_title(server_legal_name);
-    SetBookmarkSpecifics(new_value);  // Does it's own encryption checking.
-  }
-
-  MarkForSyncing();
-}
-
-void WriteNode::SetURL(const GURL& url) {
-  sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
-  new_value.set_url(url.spec());
-  SetBookmarkSpecifics(new_value);
-}
-
-void WriteNode::SetAppSpecifics(
-    const sync_pb::AppSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::app)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetAutofillSpecifics(
-    const sync_pb::AutofillSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::autofill)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetAutofillProfileSpecifics(
-    const sync_pb::AutofillProfileSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::autofill_profile)->
-      CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetBookmarkSpecifics(
-    const sync_pb::BookmarkSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::bookmark)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetNigoriSpecifics(
-    const sync_pb::NigoriSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::nigori)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetPasswordSpecifics(
-    const sync_pb::PasswordSpecificsData& data) {
-  DCHECK_EQ(syncable::PASSWORDS, GetModelType());
-
-  Cryptographer* cryptographer = GetTransaction()->GetCryptographer();
-
-  // Idempotency check to prevent unnecessary syncing: if the plaintexts match
-  // and the old ciphertext is encrypted with the most current key, there's
-  // nothing to do here.  Because each encryption is seeded with a different
-  // random value, checking for equivalence post-encryption doesn't suffice.
-  const sync_pb::EncryptedData& old_ciphertext =
-      GetEntry()->Get(SPECIFICS).GetExtension(sync_pb::password).encrypted();
-  scoped_ptr<sync_pb::PasswordSpecificsData> old_plaintext(
-      DecryptPasswordSpecifics(GetEntry()->Get(SPECIFICS), cryptographer));
-  if (old_plaintext.get() &&
-      old_plaintext->SerializeAsString() == data.SerializeAsString() &&
-      cryptographer->CanDecryptUsingDefaultKey(old_ciphertext)) {
-    return;
-  }
-
-  sync_pb::PasswordSpecifics new_value;
-  if (!cryptographer->Encrypt(data, new_value.mutable_encrypted())) {
-    NOTREACHED() << "Failed to encrypt password, possibly due to sync node "
-                 << "corruption";
-    return;
-  }
-
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::password)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetThemeSpecifics(
-    const sync_pb::ThemeSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::theme)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetSessionSpecifics(
-    const sync_pb::SessionSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::session)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetEntitySpecifics(
-    const sync_pb::EntitySpecifics& new_value) {
-  syncable::ModelType new_specifics_type =
-      syncable::GetModelTypeFromSpecifics(new_value);
-  DCHECK_NE(new_specifics_type, syncable::UNSPECIFIED);
-  VLOG(1) << "Writing entity specifics of type "
-          << syncable::ModelTypeToString(new_specifics_type);
-  // GetModelType() can be unspecified if this is the first time this
-  // node is being initialized (see PutModelType()).  Otherwise, it
-  // should match |new_specifics_type|.
-  if (GetModelType() != syncable::UNSPECIFIED) {
-    DCHECK_EQ(new_specifics_type, GetModelType());
-  }
-  browser_sync::Cryptographer* cryptographer =
-      GetTransaction()->GetCryptographer();
-
-  // Preserve unknown fields.
-  const sync_pb::EntitySpecifics& old_specifics = entry_->Get(SPECIFICS);
-  sync_pb::EntitySpecifics new_specifics;
-  new_specifics.CopyFrom(new_value);
-  new_specifics.mutable_unknown_fields()->MergeFrom(
-      old_specifics.unknown_fields());
-
-  // Will update the entry if encryption was necessary.
-  if (!UpdateEntryWithEncryption(cryptographer, new_specifics, entry_)) {
-    return;
-  }
-  if (entry_->Get(SPECIFICS).has_encrypted()) {
-    // EncryptIfNecessary already updated the entry for us and marked for
-    // syncing if it was needed. Now we just make a copy of the unencrypted
-    // specifics so that if this node is updated, we do not have to decrypt the
-    // old data. Note that this only modifies the node's local data, not the
-    // entry itself.
-    SetUnencryptedSpecifics(new_value);
-  }
-
-  DCHECK_EQ(new_specifics_type, GetModelType());
-}
-
-void WriteNode::ResetFromSpecifics() {
-  SetEntitySpecifics(GetEntitySpecifics());
-}
-
-void WriteNode::SetTypedUrlSpecifics(
-    const sync_pb::TypedUrlSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::typed_url)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetExtensionSpecifics(
-    const sync_pb::ExtensionSpecifics& new_value) {
-  sync_pb::EntitySpecifics entity_specifics;
-  entity_specifics.MutableExtension(sync_pb::extension)->CopyFrom(new_value);
-  SetEntitySpecifics(entity_specifics);
-}
-
-void WriteNode::SetExternalId(int64 id) {
-  if (GetExternalId() != id)
-    entry_->Put(syncable::LOCAL_EXTERNAL_ID, id);
-}
-
-WriteNode::WriteNode(WriteTransaction* transaction)
-    : entry_(NULL), transaction_(transaction) {
-  DCHECK(transaction);
-}
-
-WriteNode::~WriteNode() {
-  delete entry_;
-}
-
-// Find an existing node matching the ID |id|, and bind this WriteNode to it.
-// Return true on success.
-bool WriteNode::InitByIdLookup(int64 id) {
-  DCHECK(!entry_) << "Init called twice";
-  DCHECK_NE(id, kInvalidId);
-  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
-                                      syncable::GET_BY_HANDLE, id);
-  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
-          DecryptIfNecessary());
-}
-
-// Find a node by client tag, and bind this WriteNode to it.
-// Return true if the write node was found, and was not deleted.
-// Undeleting a deleted node is possible by ClientTag.
-bool WriteNode::InitByClientTagLookup(syncable::ModelType model_type,
-                                      const std::string& tag) {
-  DCHECK(!entry_) << "Init called twice";
-  if (tag.empty())
-    return false;
-
-  const std::string hash = GenerateSyncableHash(model_type, tag);
-
-  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
-                                      syncable::GET_BY_CLIENT_TAG, hash);
-  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
-          DecryptIfNecessary());
-}
-
-bool WriteNode::InitByTagLookup(const std::string& tag) {
-  DCHECK(!entry_) << "Init called twice";
-  if (tag.empty())
-    return false;
-  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
-                                      syncable::GET_BY_SERVER_TAG, tag);
-  if (!entry_->good())
-    return false;
-  if (entry_->Get(syncable::IS_DEL))
-    return false;
-  syncable::ModelType model_type = GetModelType();
-  DCHECK_EQ(syncable::NIGORI, model_type);
-  return true;
-}
-
-void WriteNode::PutModelType(syncable::ModelType model_type) {
-  // Set an empty specifics of the appropriate datatype.  The presence
-  // of the specific extension will identify the model type.
-  DCHECK(GetModelType() == model_type ||
-         GetModelType() == syncable::UNSPECIFIED);  // Immutable once set.
-
-  sync_pb::EntitySpecifics specifics;
-  syncable::AddDefaultExtensionValue(model_type, &specifics);
-  SetEntitySpecifics(specifics);
-}
-
-// Create a new node with default properties, and bind this WriteNode to it.
-// Return true on success.
-bool WriteNode::InitByCreation(syncable::ModelType model_type,
-                               const BaseNode& parent,
-                               const BaseNode* predecessor) {
-  DCHECK(!entry_) << "Init called twice";
-  // |predecessor| must be a child of |parent| or NULL.
-  if (predecessor && predecessor->GetParentId() != parent.GetId()) {
-    DCHECK(false);
-    return false;
-  }
-
-  syncable::Id parent_id = parent.GetEntry()->Get(syncable::ID);
-
-  // Start out with a dummy name.  We expect
-  // the caller to set a meaningful name after creation.
-  string dummy(kDefaultNameForNewNodes);
-
-  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
-                                      syncable::CREATE, parent_id, dummy);
-
-  if (!entry_->good())
-    return false;
-
-  // Entries are untitled folders by default.
-  entry_->Put(syncable::IS_DIR, true);
-
-  PutModelType(model_type);
-
-  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
-  PutPredecessor(predecessor);
-
-  return true;
-}
-
-// Create a new node with default properties and a client defined unique tag,
-// and bind this WriteNode to it.
-// Return true on success. If the tag exists in the database, then
-// we will attempt to undelete the node.
-// TODO(chron): Code datatype into hash tag.
-// TODO(chron): Is model type ever lost?
-bool WriteNode::InitUniqueByCreation(syncable::ModelType model_type,
-                                     const BaseNode& parent,
-                                     const std::string& tag) {
-  DCHECK(!entry_) << "Init called twice";
-
-  const std::string hash = GenerateSyncableHash(model_type, tag);
-
-  syncable::Id parent_id = parent.GetEntry()->Get(syncable::ID);
-
-  // Start out with a dummy name.  We expect
-  // the caller to set a meaningful name after creation.
-  string dummy(kDefaultNameForNewNodes);
-
-  // Check if we have this locally and need to undelete it.
-  scoped_ptr<syncable::MutableEntry> existing_entry(
-      new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
-                                 syncable::GET_BY_CLIENT_TAG, hash));
-
-  if (existing_entry->good()) {
-    if (existing_entry->Get(syncable::IS_DEL)) {
-      // Rules for undelete:
-      // BASE_VERSION: Must keep the same.
-      // ID: Essential to keep the same.
-      // META_HANDLE: Must be the same, so we can't "split" the entry.
-      // IS_DEL: Must be set to false, will cause reindexing.
-      //         This one is weird because IS_DEL is true for "update only"
-      //         items. It should be OK to undelete an update only.
-      // MTIME/CTIME: Seems reasonable to just leave them alone.
-      // IS_UNSYNCED: Must set this to true or face database insurrection.
-      //              We do this below this block.
-      // IS_UNAPPLIED_UPDATE: Either keep it the same or also set BASE_VERSION
-      //                      to SERVER_VERSION. We keep it the same here.
-      // IS_DIR: We'll leave it the same.
-      // SPECIFICS: Reset it.
-
-      existing_entry->Put(syncable::IS_DEL, false);
-
-      // Client tags are immutable and must be paired with the ID.
-      // If a server update comes down with an ID and client tag combo,
-      // and it already exists, always overwrite it and store only one copy.
-      // We have to undelete entries because we can't disassociate IDs from
-      // tags and updates.
-
-      existing_entry->Put(syncable::NON_UNIQUE_NAME, dummy);
-      existing_entry->Put(syncable::PARENT_ID, parent_id);
-      entry_ = existing_entry.release();
-    } else {
-      return false;
-    }
-  } else {
-    entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
-                                        syncable::CREATE, parent_id, dummy);
-    if (!entry_->good()) {
-      return false;
-    }
-
-    // Only set IS_DIR for new entries. Don't bitflip undeleted ones.
-    entry_->Put(syncable::UNIQUE_CLIENT_TAG, hash);
-  }
-
-  // We don't support directory and tag combinations.
-  entry_->Put(syncable::IS_DIR, false);
-
-  // Will clear specifics data.
-  PutModelType(model_type);
-
-  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
-  PutPredecessor(NULL);
-
-  return true;
-}
-
-bool WriteNode::SetPosition(const BaseNode& new_parent,
-                            const BaseNode* predecessor) {
-  // |predecessor| must be a child of |new_parent| or NULL.
-  if (predecessor && predecessor->GetParentId() != new_parent.GetId()) {
-    DCHECK(false);
-    return false;
-  }
-
-  syncable::Id new_parent_id = new_parent.GetEntry()->Get(syncable::ID);
-
-  // Filter out redundant changes if both the parent and the predecessor match.
-  if (new_parent_id == entry_->Get(syncable::PARENT_ID)) {
-    const syncable::Id& old = entry_->Get(syncable::PREV_ID);
-    if ((!predecessor && old.IsRoot()) ||
-        (predecessor && (old == predecessor->GetEntry()->Get(syncable::ID)))) {
-      return true;
-    }
-  }
-
-  // Atomically change the parent. This will fail if it would
-  // introduce a cycle in the hierarchy.
-  if (!entry_->Put(syncable::PARENT_ID, new_parent_id))
-    return false;
-
-  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
-  PutPredecessor(predecessor);
-
-  return true;
-}
-
-const syncable::Entry* WriteNode::GetEntry() const {
-  return entry_;
-}
-
-const BaseTransaction* WriteNode::GetTransaction() const {
-  return transaction_;
-}
-
-void WriteNode::Remove() {
-  entry_->Put(syncable::IS_DEL, true);
-  MarkForSyncing();
-}
-
-void WriteNode::PutPredecessor(const BaseNode* predecessor) {
-  syncable::Id predecessor_id = predecessor ?
-      predecessor->GetEntry()->Get(syncable::ID) : syncable::Id();
-  entry_->PutPredecessor(predecessor_id);
-  // Mark this entry as unsynced, to wake up the syncer.
-  MarkForSyncing();
-}
-
-void WriteNode::SetFaviconBytes(const vector<unsigned char>& bytes) {
-  sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
-  new_value.set_favicon(bytes.empty() ? NULL : &bytes[0], bytes.size());
-  SetBookmarkSpecifics(new_value);
-}
-
-void WriteNode::MarkForSyncing() {
-  syncable::MarkForSyncing(entry_);
-}
-
-//////////////////////////////////////////////////////////////////////////
-// ReadNode member definitions
-ReadNode::ReadNode(const BaseTransaction* transaction)
-    : entry_(NULL), transaction_(transaction) {
-  DCHECK(transaction);
-}
-
-ReadNode::ReadNode() {
-  entry_ = NULL;
-  transaction_ = NULL;
-}
-
-ReadNode::~ReadNode() {
-  delete entry_;
-}
-
-void ReadNode::InitByRootLookup() {
-  DCHECK(!entry_) << "Init called twice";
-  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
-  entry_ = new syncable::Entry(trans, syncable::GET_BY_ID, trans->root_id());
-  if (!entry_->good())
-    DCHECK(false) << "Could not lookup root node for reading.";
-}
-
-bool ReadNode::InitByIdLookup(int64 id) {
-  DCHECK(!entry_) << "Init called twice";
-  DCHECK_NE(id, kInvalidId);
-  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
-  entry_ = new syncable::Entry(trans, syncable::GET_BY_HANDLE, id);
-  if (!entry_->good())
-    return false;
-  if (entry_->Get(syncable::IS_DEL))
-    return false;
-  syncable::ModelType model_type = GetModelType();
-  LOG_IF(WARNING, model_type == syncable::UNSPECIFIED ||
-                  model_type == syncable::TOP_LEVEL_FOLDER)
-      << "SyncAPI InitByIdLookup referencing unusual object.";
-  return DecryptIfNecessary();
-}
-
-bool ReadNode::InitByClientTagLookup(syncable::ModelType model_type,
-                                     const std::string& tag) {
-  DCHECK(!entry_) << "Init called twice";
-  if (tag.empty())
-    return false;
-
-  const std::string hash = GenerateSyncableHash(model_type, tag);
-
-  entry_ = new syncable::Entry(transaction_->GetWrappedTrans(),
-                               syncable::GET_BY_CLIENT_TAG, hash);
-  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
-          DecryptIfNecessary());
-}
-
-const syncable::Entry* ReadNode::GetEntry() const {
-  return entry_;
-}
-
-const BaseTransaction* ReadNode::GetTransaction() const {
-  return transaction_;
-}
-
-bool ReadNode::InitByTagLookup(const std::string& tag) {
-  DCHECK(!entry_) << "Init called twice";
-  if (tag.empty())
-    return false;
-  syncable::BaseTransaction* trans = transaction_->GetWrappedTrans();
-  entry_ = new syncable::Entry(trans, syncable::GET_BY_SERVER_TAG, tag);
-  if (!entry_->good())
-    return false;
-  if (entry_->Get(syncable::IS_DEL))
-    return false;
-  syncable::ModelType model_type = GetModelType();
-  LOG_IF(WARNING, model_type == syncable::UNSPECIFIED ||
-                  model_type == syncable::TOP_LEVEL_FOLDER)
-      << "SyncAPI InitByTagLookup referencing unusually typed object.";
-  return DecryptIfNecessary();
-}
-
-//////////////////////////////////////////////////////////////////////////
-// ReadTransaction member definitions
-ReadTransaction::ReadTransaction(const tracked_objects::Location& from_here,
-                                 UserShare* share)
-    : BaseTransaction(share),
-      transaction_(NULL),
-      close_transaction_(true) {
-  transaction_ = new syncable::ReadTransaction(from_here, GetLookup());
-}
-
-ReadTransaction::ReadTransaction(UserShare* share,
-                                 syncable::BaseTransaction* trans)
-    : BaseTransaction(share),
-      transaction_(trans),
-      close_transaction_(false) {}
-
-ReadTransaction::~ReadTransaction() {
-  if (close_transaction_) {
-    delete transaction_;
-  }
-}
-
-syncable::BaseTransaction* ReadTransaction::GetWrappedTrans() const {
-  return transaction_;
-}
-
-//////////////////////////////////////////////////////////////////////////
-// WriteTransaction member definitions
-WriteTransaction::WriteTransaction(const tracked_objects::Location& from_here,
-                                   UserShare* share)
-    : BaseTransaction(share),
-      transaction_(NULL) {
-  transaction_ = new syncable::WriteTransaction(from_here, syncable::SYNCAPI,
-                                                GetLookup());
-}
-
-WriteTransaction::~WriteTransaction() {
-  delete transaction_;
-}
-
-syncable::BaseTransaction* WriteTransaction::GetWrappedTrans() const {
-  return transaction_;
-}
-
 SyncManager::ChangeRecord::ChangeRecord()
     : id(kInvalidId), action(ACTION_ADD) {}
 
@@ -1204,12 +156,6 @@ const sync_pb::PasswordSpecificsData&
   return unencrypted_;
 }
 
-syncable::ModelTypeSet GetEncryptedTypes(
-    const sync_api::BaseTransaction* trans) {
-  Cryptographer* cryptographer = trans->GetCryptographer();
-  return cryptographer->GetEncryptedTypes();
-}
-
 //////////////////////////////////////////////////////////////////////////
 // SyncManager's implementation: SyncManager::SyncInternal
 class SyncManager::SyncInternal
@@ -1709,7 +655,6 @@ void SyncManager::UpdateEnabledTypes() {
   data_->UpdateEnabledTypes();
 }
 
-
 bool SyncManager::InitialSyncEndedForAllEnabledTypes() {
   return data_->InitialSyncEndedForAllEnabledTypes();
 }
@@ -2548,7 +1493,6 @@ void SyncManager::SyncInternal::RequestNudge(
         ModelTypeBitSet(), location);
 }
 
-
 void SyncManager::SyncInternal::RequestNudgeForDataType(
     const tracked_objects::Location& nudge_location,
     const ModelType& type) {
@@ -2956,7 +1900,6 @@ void SyncManager::SyncInternal::StoreState(
   lookup->SaveChanges();
 }
 
-
 // Note: it is possible that an observer will remove itself after we have made
 // a copy, but before the copy is consumed. This could theoretically result
 // in accessing a garbage pointer, but can only occur when an about:sync window
@@ -3014,21 +1957,6 @@ void SyncManager::SyncInternal::SaveChanges() {
   lookup->SaveChanges();
 }
 
-//////////////////////////////////////////////////////////////////////////
-// BaseTransaction member definitions
-BaseTransaction::BaseTransaction(UserShare* share)
-    : lookup_(NULL) {
-  DCHECK(share && share->dir_manager.get());
-  lookup_ = new syncable::ScopedDirLookup(share->dir_manager.get(),
-                                          share->name);
-  cryptographer_ = share->dir_manager->GetCryptographer(this);
-  if (!(lookup_->good()))
-    DCHECK(false) << "ScopedDirLookup failed on valid DirManager.";
-}
-BaseTransaction::~BaseTransaction() {
-  delete lookup_;
-}
-
 UserShare* SyncManager::GetUserShare() const {
   return data_->GetUserShare();
 }
@@ -3080,4 +2008,40 @@ void SyncManager::TriggerOnIncomingNotificationForTest(
   data_->OnIncomingNotification(model_types_with_payloads);
 }
 
+// Helper function that converts a PassphraseRequiredReason value to a string.
+std::string PassphraseRequiredReasonToString(
+    PassphraseRequiredReason reason) {
+  switch (reason) {
+    case REASON_PASSPHRASE_NOT_REQUIRED:
+      return "REASON_PASSPHRASE_NOT_REQUIRED";
+    case REASON_ENCRYPTION:
+      return "REASON_ENCRYPTION";
+    case REASON_DECRYPTION:
+      return "REASON_DECRYPTION";
+    case REASON_SET_PASSPHRASE_FAILED:
+      return "REASON_SET_PASSPHRASE_FAILED";
+    default:
+      NOTREACHED();
+      return "INVALID_REASON";
+  }
+}
+
+// Helper function to determine if initial sync had ended for types.
+bool InitialSyncEndedForTypes(syncable::ModelTypeSet types,
+                              sync_api::UserShare* share) {
+  syncable::ScopedDirLookup lookup(share->dir_manager.get(),
+                                   share->name);
+  if (!lookup.good()) {
+    DCHECK(false) << "ScopedDirLookup failed when checking initial sync";
+    return false;
+  }
+
+  for (syncable::ModelTypeSet::const_iterator i = types.begin();
+       i != types.end(); ++i) {
+    if (!lookup->initial_sync_ended_for_type(*i))
+      return false;
+  }
+  return true;
+}
+
 }  // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/sync_manager.h b/chrome/browser/sync/internal_api/sync_manager.h
new file mode 100644
index 0000000..14350a4
--- /dev/null
+++ b/chrome/browser/sync/internal_api/sync_manager.h
@@ -0,0 +1,546 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_SYNC_MANAGER_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_SYNC_MANAGER_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/callback_old.h"
+#include "base/memory/linked_ptr.h"
+#include "chrome/browser/sync/engine/configure_reason.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+#include "chrome/browser/sync/syncable/model_type.h"
+#include "chrome/browser/sync/weak_handle.h"
+#include "chrome/common/net/gaia/google_service_auth_error.h"
+
+class FilePath;
+
+namespace base {
+class DictionaryValue;
+}  // namespace base
+
+namespace browser_sync {
+class JsBackend;
+class JsEventHandler;
+class ModelSafeWorkerRegistrar;
+
+namespace sessions {
+struct SyncSessionSnapshot;
+}  // namespace sessions
+}  // namespace browser_sync
+
+namespace sync_notifier {
+class SyncNotifier;
+}  // namespace sync_notifier
+
+namespace sync_pb {
+class PasswordSpecificsData;
+}  // namespace sync_pb
+
+namespace sync_api {
+
+class BaseTransaction;
+class HttpPostProviderFactory;
+struct UserShare;
+
+// Reasons due to which browser_sync::Cryptographer might require a passphrase.
+enum PassphraseRequiredReason {
+  REASON_PASSPHRASE_NOT_REQUIRED = 0,  // Initial value.
+  REASON_ENCRYPTION = 1,               // The cryptographer requires a
+                                       // passphrase for its first attempt at
+                                       // encryption. Happens only during
+                                       // migration or upgrade.
+  REASON_DECRYPTION = 2,               // The cryptographer requires a
+                                       // passphrase for its first attempt at
+                                       // decryption.
+  REASON_SET_PASSPHRASE_FAILED = 3,    // The cryptographer requires a new
+                                       // passphrase because its attempt at
+                                       // decryption with the cached passphrase
+                                       // was unsuccessful.
+};
+
+// Contains everything needed to talk to and identify a user account.
+struct SyncCredentials {
+  std::string email;
+  std::string sync_token;
+};
+
+// SyncManager encapsulates syncable::DirectoryManager and serves as the parent
+// of all other objects in the sync API.  SyncManager is thread-safe.  If
+// multiple threads interact with the same local sync repository (i.e. the
+// same sqlite database), they should share a single SyncManager instance.  The
+// caller should typically create one SyncManager for the lifetime of a user
+// session.
+class SyncManager {
+ public:
+  // SyncInternal contains the implementation of SyncManager, while abstracting
+  // internal types from clients of the interface.
+  class SyncInternal;
+
+  // TODO(zea): One day get passwords playing nicely with the rest of encryption
+  // and get rid of this.
+  class ExtraPasswordChangeRecordData {
+   public:
+    ExtraPasswordChangeRecordData();
+    explicit ExtraPasswordChangeRecordData(
+        const sync_pb::PasswordSpecificsData& data);
+    virtual ~ExtraPasswordChangeRecordData();
+
+    // Transfers ownership of the DictionaryValue to the caller.
+    virtual base::DictionaryValue* ToValue() const;
+
+    const sync_pb::PasswordSpecificsData& unencrypted() const;
+   private:
+    sync_pb::PasswordSpecificsData unencrypted_;
+  };
+
+  // ChangeRecord indicates a single item that changed as a result of a sync
+  // operation.  This gives the sync id of the node that changed, and the type
+  // of change.  To get the actual property values after an ADD or UPDATE, the
+  // client should get the node with InitByIdLookup(), using the provided id.
+  struct ChangeRecord {
+    enum Action {
+      ACTION_ADD,
+      ACTION_DELETE,
+      ACTION_UPDATE,
+    };
+    ChangeRecord();
+    ~ChangeRecord();
+
+    // Transfers ownership of the DictionaryValue to the caller.
+    base::DictionaryValue* ToValue(const BaseTransaction* trans) const;
+
+    int64 id;
+    Action action;
+    sync_pb::EntitySpecifics specifics;
+    linked_ptr<ExtraPasswordChangeRecordData> extra;
+  };
+
+  // Status encapsulates detailed state about the internals of the SyncManager.
+  struct Status {
+    // Summary is a distilled set of important information that the end-user may
+    // wish to be informed about (through UI, for example). Note that if a
+    // summary state requires user interaction (such as auth failures), more
+    // detailed information may be contained in additional status fields.
+    enum Summary {
+      // The internal instance is in an unrecognizable state. This should not
+      // happen.
+      INVALID = 0,
+      // Can't connect to server, but there are no pending changes in
+      // our local cache.
+      OFFLINE,
+      // Can't connect to server, and there are pending changes in our
+      // local cache.
+      OFFLINE_UNSYNCED,
+      // Connected and syncing.
+      SYNCING,
+      // Connected, no pending changes.
+      READY,
+      // Internal sync error.
+      CONFLICT,
+      // Can't connect to server, and we haven't completed the initial
+      // sync yet.  So there's nothing we can do but wait for the server.
+      OFFLINE_UNUSABLE,
+
+      SUMMARY_STATUS_COUNT,
+    };
+
+    Status();
+    ~Status();
+
+    Summary summary;
+    bool authenticated;      // Successfully authenticated via GAIA.
+    bool server_up;          // True if we have received at least one good
+                             // reply from the server.
+    bool server_reachable;   // True if we received any reply from the server.
+    bool server_broken;      // True of the syncer is stopped because of server
+                             // issues.
+    bool notifications_enabled;  // True only if subscribed for notifications.
+
+    // Notifications counters updated by the actions in synapi.
+    int notifications_received;
+    int notifiable_commits;
+
+    // The max number of consecutive errors from any component.
+    int max_consecutive_errors;
+
+    int unsynced_count;
+
+    int conflicting_count;
+    bool syncing;
+    // True after a client has done a first sync.
+    bool initial_sync_ended;
+    // True if any syncer is stuck.
+    bool syncer_stuck;
+
+    // Total updates available.  If zero, nothing left to download.
+    int64 updates_available;
+    // Total updates received by the syncer since browser start.
+    int updates_received;
+
+    // Of updates_received, how many were tombstones.
+    int tombstone_updates_received;
+    bool disk_full;
+
+    // Total number of overwrites due to conflict resolver since browser start.
+    int num_local_overwrites_total;
+    int num_server_overwrites_total;
+
+    // Count of empty and non empty getupdates;
+    int nonempty_get_updates;
+    int empty_get_updates;
+
+    // Count of useless and useful syncs we perform.
+    int useless_sync_cycles;
+    int useful_sync_cycles;
+
+    // Encryption related.
+    syncable::ModelTypeSet encrypted_types;
+    bool cryptographer_ready;
+    bool crypto_has_pending_keys;
+  };
+
+  // An interface the embedding application implements to receive notifications
+  // from the SyncManager.  Register an observer via SyncManager::AddObserver.
+  // This observer is an event driven model as the events may be raised from
+  // different internal threads, and simply providing an "OnStatusChanged" type
+  // notification complicates things such as trying to determine "what changed",
+  // if different members of the Status object are modified from different
+  // threads.  This way, the event is explicit, and it is safe for the Observer
+  // to dispatch to a native thread or synchronize accordingly.
+  class Observer {
+   public:
+    // Notify the observer that changes have been applied to the sync model.
+    //
+    // This will be invoked on the same thread as on which ApplyChanges was
+    // called. |changes| is an array of size |change_count|, and contains the
+    // ID of each individual item that was changed. |changes| exists only for
+    // the duration of the call. If items of multiple data types change at
+    // the same time, this method is invoked once per data type and |changes|
+    // is restricted to items of the ModelType indicated by |model_type|.
+    // Because the observer is passed a |trans|, the observer can assume a
+    // read lock on the sync model that will be released after the function
+    // returns.
+    //
+    // The SyncManager constructs |changes| in the following guaranteed order:
+    //
+    // 1. Deletions, from leaves up to parents.
+    // 2. Updates to existing items with synced parents & predecessors.
+    // 3. New items with synced parents & predecessors.
+    // 4. Items with parents & predecessors in |changes|.
+    // 5. Repeat #4 until all items are in |changes|.
+    //
+    // Thus, an implementation of OnChangesApplied should be able to
+    // process the change records in the order without having to worry about
+    // forward dependencies.  But since deletions come before reparent
+    // operations, a delete may temporarily orphan a node that is
+    // updated later in the list.
+    virtual void OnChangesApplied(syncable::ModelType model_type,
+                                  const BaseTransaction* trans,
+                                  const ChangeRecord* changes,
+                                  int change_count) = 0;
+
+    // OnChangesComplete gets called when the TransactionComplete event is
+    // posted (after OnChangesApplied finishes), after the transaction lock
+    // and the change channel mutex are released.
+    //
+    // The purpose of this function is to support processors that require
+    // split-transactions changes. For example, if a model processor wants to
+    // perform blocking I/O due to a change, it should calculate the changes
+    // while holding the transaction lock (from within OnChangesApplied), buffer
+    // those changes, let the transaction fall out of scope, and then commit
+    // those changes from within OnChangesComplete (postponing the blocking
+    // I/O to when it no longer holds any lock).
+    virtual void OnChangesComplete(syncable::ModelType model_type) = 0;
+
+    // A round-trip sync-cycle took place and the syncer has resolved any
+    // conflicts that may have arisen.
+    virtual void OnSyncCycleCompleted(
+        const browser_sync::sessions::SyncSessionSnapshot* snapshot) = 0;
+
+    // Called when user interaction may be required due to an auth problem.
+    virtual void OnAuthError(const GoogleServiceAuthError& auth_error) = 0;
+
+    // Called when a new auth token is provided by the sync server.
+    virtual void OnUpdatedToken(const std::string& token) = 0;
+
+    // Called when user interaction is required to obtain a valid passphrase.
+    // - If the passphrase is required for encryption, |reason| will be
+    //   REASON_ENCRYPTION.
+    // - If the passphrase is required for the decryption of data that has
+    //   already been encrypted, |reason| will be REASON_DECRYPTION.
+    // - If the passphrase is required because decryption failed, and a new
+    //   passphrase is required, |reason| will be REASON_SET_PASSPHRASE_FAILED.
+    virtual void OnPassphraseRequired(PassphraseRequiredReason reason) = 0;
+
+    // Called when the passphrase provided by the user has been accepted and is
+    // now used to encrypt sync data.  |bootstrap_token| is an opaque base64
+    // encoded representation of the key generated by the accepted passphrase,
+    // and is provided to the observer for persistence purposes and use in a
+    // future initialization of sync (e.g. after restart).
+    virtual void OnPassphraseAccepted(const std::string& bootstrap_token) = 0;
+
+    // Called when initialization is complete to the point that SyncManager can
+    // process changes. This does not necessarily mean authentication succeeded
+    // or that the SyncManager is online.
+    // IMPORTANT: Creating any type of transaction before receiving this
+    // notification is illegal!
+    // WARNING: Calling methods on the SyncManager before receiving this
+    // message, unless otherwise specified, produces undefined behavior.
+    //
+    // |js_backend| is what about:sync interacts with.  It can emit
+    // the following events:
+
+    /**
+     * @param {{ enabled: boolean }} details A dictionary containing:
+     *     - enabled: whether or not notifications are enabled.
+     */
+    // function onNotificationStateChange(details);
+
+    /**
+     * @param {{ changedTypes: Array.<string> }} details A dictionary
+     *     containing:
+     *     - changedTypes: a list of types (as strings) for which there
+             are new updates.
+     */
+    // function onIncomingNotification(details);
+
+    // Also, it responds to the following messages (all other messages
+    // are ignored):
+
+    /**
+     * Gets the current notification state.
+     *
+     * @param {function(boolean)} callback Called with whether or not
+     *     notifications are enabled.
+     */
+    // function getNotificationState(callback);
+
+    /**
+     * Gets details about the root node.
+     *
+     * @param {function(!Object)} callback Called with details about the
+     *     root node.
+     */
+    // TODO(akalin): Change this to getRootNodeId or eliminate it
+    // entirely.
+    // function getRootNodeDetails(callback);
+
+    /**
+     * Gets summary information for a list of ids.
+     *
+     * @param {Array.<string>} idList List of 64-bit ids in decimal
+     *     string form.
+     * @param {Array.<{id: string, title: string, isFolder: boolean}>}
+     * callback Called with summaries for the nodes in idList that
+     *     exist.
+     */
+    // function getNodeSummariesById(idList, callback);
+
+    /**
+     * Gets detailed information for a list of ids.
+     *
+     * @param {Array.<string>} idList List of 64-bit ids in decimal
+     *     string form.
+     * @param {Array.<!Object>} callback Called with detailed
+     *     information for the nodes in idList that exist.
+     */
+    // function getNodeDetailsById(idList, callback);
+
+    /**
+     * Gets child ids for a given id.
+     *
+     * @param {string} id 64-bit id in decimal string form of the parent
+     *     node.
+     * @param {Array.<string>} callback Called with the (possibly empty)
+     *     list of child ids.
+     */
+    // function getChildNodeIds(id);
+
+    virtual void OnInitializationComplete(
+        const browser_sync::WeakHandle<browser_sync::JsBackend>&
+            js_backend) = 0;
+
+    // We are no longer permitted to communicate with the server. Sync should
+    // be disabled and state cleaned up at once.  This can happen for a number
+    // of reasons, e.g. swapping from a test instance to production, or a
+    // global stop syncing operation has wiped the store.
+    virtual void OnStopSyncingPermanently() = 0;
+
+    // After a request to clear server data, these callbacks are invoked to
+    // indicate success or failure.
+    virtual void OnClearServerDataSucceeded() = 0;
+    virtual void OnClearServerDataFailed() = 0;
+
+    // Called after we finish encrypting all appropriate datatypes.
+    virtual void OnEncryptionComplete(
+        const syncable::ModelTypeSet& encrypted_types) = 0;
+
+   protected:
+    virtual ~Observer();
+  };
+
+  typedef Callback0::Type ModeChangeCallback;
+
+  // Create an uninitialized SyncManager.  Callers must Init() before using.
+  explicit SyncManager(const std::string& name);
+  virtual ~SyncManager();
+
+  // Initialize the sync manager.  |database_location| specifies the path of
+  // the directory in which to locate a sqlite repository storing the syncer
+  // backend state. Initialization will open the database, or create it if it
+  // does not already exist. Returns false on failure.
+  // |event_handler| is the JsEventHandler used to propagate events to
+  // chrome://sync-internals.  |event_handler| may be uninitialized.
+  // |sync_server_and_path| and |sync_server_port| represent the Chrome sync
+  // server to use, and |use_ssl| specifies whether to communicate securely;
+  // the default is false.
+  // |post_factory| will be owned internally and used to create
+  // instances of an HttpPostProvider.
+  // |model_safe_worker| ownership is given to the SyncManager.
+  // |user_agent| is a 7-bit ASCII string suitable for use as the User-Agent
+  // HTTP header. Used internally when collecting stats to classify clients.
+  // |sync_notifier| is owned and used to listen for notifications.
+  bool Init(const FilePath& database_location,
+            const browser_sync::WeakHandle<browser_sync::JsEventHandler>&
+                event_handler,
+            const std::string& sync_server_and_path,
+            int sync_server_port,
+            bool use_ssl,
+            HttpPostProviderFactory* post_factory,
+            browser_sync::ModelSafeWorkerRegistrar* registrar,
+            const std::string& user_agent,
+            const SyncCredentials& credentials,
+            sync_notifier::SyncNotifier* sync_notifier,
+            const std::string& restored_key_for_bootstrapping,
+            bool setup_for_test_mode);
+
+  // Returns the username last used for a successful authentication.
+  // Returns empty if there is no such username.
+  const std::string& GetAuthenticatedUsername();
+
+  // Check if the database has been populated with a full "initial" download of
+  // sync items for each data type currently present in the routing info.
+  // Prerequisite for calling this is that OnInitializationComplete has been
+  // called.
+  bool InitialSyncEndedForAllEnabledTypes();
+
+  // Update tokens that we're using in Sync. Email must stay the same.
+  void UpdateCredentials(const SyncCredentials& credentials);
+
+  // Called when the user disables or enables a sync type.
+  void UpdateEnabledTypes();
+
+  // Put the syncer in normal mode ready to perform nudges and polls.
+  void StartSyncingNormally();
+
+  // Attempt to set the passphrase. If the passphrase is valid,
+  // OnPassphraseAccepted will be fired to notify the ProfileSyncService and the
+  // syncer will be nudged so that any update that was waiting for this
+  // passphrase gets applied as soon as possible.
+  // If the passphrase in invalid, OnPassphraseRequired will be fired.
+  // Calling this metdod again is the appropriate course of action to "retry"
+  // with a new passphrase.
+  // |is_explicit| is true if the call is in response to the user explicitly
+  // setting a passphrase as opposed to implicitly (from the users' perspective)
+  // using their Google Account password.  An implicit SetPassphrase will *not*
+  // *not* override an explicit passphrase set previously.
+  void SetPassphrase(const std::string& passphrase, bool is_explicit);
+
+  // Set the datatypes we want to encrypt and encrypt any nodes as necessary.
+  // Note: |encrypted_types| will be unioned with the current set of encrypted
+  // types, as we do not currently support decrypting datatypes.
+  void EncryptDataTypes(const syncable::ModelTypeSet& encrypted_types);
+
+  // Puts the SyncScheduler into a mode where no normal nudge or poll traffic
+  // will occur, but calls to RequestConfig will be supported.  If |callback|
+  // is provided, it will be invoked (from the internal SyncScheduler) when
+  // the thread has changed to configuration mode.
+  void StartConfigurationMode(ModeChangeCallback* callback);
+
+  // Switches the mode of operation to CONFIGURATION_MODE and
+  // schedules a config task to fetch updates for |types|.
+  void RequestConfig(const syncable::ModelTypeBitSet& types,
+     sync_api::ConfigureReason reason);
+
+  void RequestCleanupDisabledTypes();
+
+  // Request a clearing of all data on the server
+  void RequestClearServerData();
+
+  // Adds a listener to be notified of sync events.
+  // NOTE: It is OK (in fact, it's probably a good idea) to call this before
+  // having received OnInitializationCompleted.
+  void AddObserver(Observer* observer);
+
+  // Remove the given observer.  Make sure to call this if the
+  // Observer is being destroyed so the SyncManager doesn't
+  // potentially dereference garbage.
+  void RemoveObserver(Observer* observer);
+
+  // Status-related getters. Typically GetStatusSummary will suffice, but
+  // GetDetailedSyncStatus can be useful for gathering debug-level details of
+  // the internals of the sync engine.
+  Status::Summary GetStatusSummary() const;
+  Status GetDetailedStatus() const;
+
+  // Whether or not the Nigori node is encrypted using an explicit passphrase.
+  bool IsUsingExplicitPassphrase();
+
+  // Get the internal implementation for use by BaseTransaction, etc.
+  SyncInternal* GetImpl() const;
+
+  // Call periodically from a database-safe thread to persist recent changes
+  // to the syncapi model.
+  void SaveChanges();
+
+  void RequestEarlyExit();
+
+  // Issue a final SaveChanges, close sqlite handles, and stop running threads.
+  // Must be called from the same thread that called Init().
+  void Shutdown();
+
+  UserShare* GetUserShare() const;
+
+  // Inform the cryptographer of the most recent passphrase and set of encrypted
+  // types (from nigori node), then ensure all data that needs encryption is
+  // encrypted with the appropriate passphrase.
+  // Note: opens a transaction and can trigger ON_PASSPHRASE_REQUIRED, so must
+  // only be called after syncapi has been initialized.
+  void RefreshEncryption();
+
+  syncable::ModelTypeSet GetEncryptedDataTypes() const;
+
+  // Uses a read-only transaction to determine if the directory being synced has
+  // any remaining unsynced items.
+  bool HasUnsyncedItems() const;
+
+  // Logs the list of unsynced meta handles.
+  void LogUnsyncedItems(int level) const;
+
+  // Functions used for testing.
+
+  void TriggerOnNotificationStateChangeForTest(
+      bool notifications_enabled);
+
+  void TriggerOnIncomingNotificationForTest(
+      const syncable::ModelTypeBitSet& model_types);
+
+ private:
+  // An opaque pointer to the nested private class.
+  SyncInternal* data_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncManager);
+};
+
+bool InitialSyncEndedForTypes(syncable::ModelTypeSet types, UserShare* share);
+
+// Returns the string representation of a PassphraseRequiredReason value.
+std::string PassphraseRequiredReasonToString(PassphraseRequiredReason reason);
+
+} // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_SYNC_MANAGER_H_
diff --git a/chrome/browser/sync/engine/syncapi_mock.h b/chrome/browser/sync/internal_api/syncapi_mock.h
index 8e71aa8..dd56d7a 100644
--- a/chrome/browser/sync/engine/syncapi_mock.h
+++ b/chrome/browser/sync/internal_api/syncapi_mock.h
@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_MOCK_H_
-#define CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_MOCK_H_
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_SYNCAPI_MOCK_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_SYNCAPI_MOCK_H_
 #pragma once
 
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/syncable/syncable.h"
 #include "chrome/browser/sync/syncable/syncable_mock.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -23,5 +23,5 @@ class MockWriteTransaction : public sync_api::WriteTransaction {
   }
 };
 
-#endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_MOCK_H_
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_SYNCAPI_MOCK_H_
 
diff --git a/chrome/browser/sync/engine/syncapi_unittest.cc b/chrome/browser/sync/internal_api/syncapi_unittest.cc
index cc3fdba..17f77e9 100644
--- a/chrome/browser/sync/engine/syncapi_unittest.cc
+++ b/chrome/browser/sync/internal_api/syncapi_unittest.cc
@@ -25,7 +25,11 @@
 #include "chrome/browser/sync/engine/http_post_provider_interface.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/engine/nigori_util.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/js/js_arg_list.h"
 #include "chrome/browser/sync/js/js_backend.h"
 #include "chrome/browser/sync/js/js_event_handler.h"
@@ -35,8 +39,8 @@
 #include "chrome/browser/sync/notifier/sync_notifier_observer.h"
 #include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
 #include "chrome/browser/sync/protocol/password_specifics.pb.h"
-#include "chrome/browser/sync/protocol/sync.pb.h"
 #include "chrome/browser/sync/protocol/proto_value_conversions.h"
+#include "chrome/browser/sync/protocol/sync.pb.h"
 #include "chrome/browser/sync/sessions/sync_session.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/browser/sync/syncable/syncable.h"
diff --git a/chrome/browser/sync/internal_api/user_share.cc b/chrome/browser/sync/internal_api/user_share.cc
new file mode 100644
index 0000000..3cb70a0
--- /dev/null
+++ b/chrome/browser/sync/internal_api/user_share.cc
@@ -0,0 +1,15 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/internal_api/user_share.h"
+
+#include "chrome/browser/sync/syncable/directory_manager.h"
+
+namespace sync_api {
+
+UserShare::UserShare() {}
+
+UserShare::~UserShare() {}
+
+}
diff --git a/chrome/browser/sync/internal_api/user_share.h b/chrome/browser/sync/internal_api/user_share.h
new file mode 100644
index 0000000..edc0932
--- /dev/null
+++ b/chrome/browser/sync/internal_api/user_share.h
@@ -0,0 +1,37 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_USER_SHARE_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_USER_SHARE_H_
+#pragma once
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+
+namespace syncable {
+class DirectoryManager;
+}
+
+namespace sync_api {
+
+// A UserShare encapsulates the syncable pieces that represent an authenticated
+// user and their data (share).
+// This encompasses all pieces required to build transaction objects on the
+// syncable share.
+struct UserShare {
+  UserShare();
+  ~UserShare();
+
+  // The DirectoryManager itself, which is the parent of Transactions and can
+  // be shared across multiple threads (unlike Directory).
+  scoped_ptr<syncable::DirectoryManager> dir_manager;
+
+  // The username of the sync user.
+  std::string name;
+};
+
+}
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_USER_SHARE_H_
diff --git a/chrome/browser/sync/internal_api/write_node.cc b/chrome/browser/sync/internal_api/write_node.cc
new file mode 100644
index 0000000..875d644
--- /dev/null
+++ b/chrome/browser/sync/internal_api/write_node.cc
@@ -0,0 +1,538 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/internal_api/write_node.h"
+
+#include "base/json/json_writer.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/sync/engine/nigori_util.h"
+#include "chrome/browser/sync/engine/syncapi_internal.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
+#include "chrome/browser/sync/protocol/app_specifics.pb.h"
+#include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
+#include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
+#include "chrome/browser/sync/protocol/extension_specifics.pb.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+#include "chrome/browser/sync/protocol/session_specifics.pb.h"
+#include "chrome/browser/sync/protocol/theme_specifics.pb.h"
+#include "chrome/browser/sync/protocol/typed_url_specifics.pb.h"
+#include "chrome/browser/sync/syncable/syncable.h"
+#include "chrome/browser/sync/util/cryptographer.h"
+
+using browser_sync::Cryptographer;
+using std::string;
+using std::vector;
+using syncable::kEncryptedString;
+using syncable::SPECIFICS;
+
+namespace sync_api {
+
+static const char kDefaultNameForNewNodes[] = " ";
+
+//////////////////////////////////////////////////////////////////////////
+// Static helper functions.
+
+// When taking a name from the syncapi, append a space if it matches the
+// pattern of a server-illegal name followed by zero or more spaces.
+static void SyncAPINameToServerName(const std::wstring& sync_api_name,
+                                    std::string* out) {
+  *out = WideToUTF8(sync_api_name);
+  if (IsNameServerIllegalAfterTrimming(*out))
+    out->append(" ");
+}
+
+bool WriteNode::UpdateEntryWithEncryption(
+    browser_sync::Cryptographer* cryptographer,
+    const sync_pb::EntitySpecifics& new_specifics,
+    syncable::MutableEntry* entry) {
+  syncable::ModelType type = syncable::GetModelTypeFromSpecifics(new_specifics);
+  DCHECK_GE(type, syncable::FIRST_REAL_MODEL_TYPE);
+  syncable::ModelTypeSet encrypted_types = cryptographer->GetEncryptedTypes();
+
+  sync_pb::EntitySpecifics generated_specifics;
+  if (type == syncable::PASSWORDS ||        // Has own encryption scheme.
+      type == syncable::NIGORI ||           // Encrypted separately.
+      encrypted_types.count(type) == 0 ||
+      new_specifics.has_encrypted()) {
+    // No encryption required.
+    generated_specifics.CopyFrom(new_specifics);
+  } else {
+    // Encrypt new_specifics into generated_specifics.
+    if (VLOG_IS_ON(2)) {
+      scoped_ptr<DictionaryValue> value(entry->ToValue());
+      std::string info;
+      base::JSONWriter::Write(value.get(), true, &info);
+      VLOG(2) << "Encrypting specifics of type "
+              << syncable::ModelTypeToString(type)
+              << " with content: "
+              << info;
+    }
+    if (!cryptographer->is_initialized())
+      return false;
+    syncable::AddDefaultExtensionValue(type, &generated_specifics);
+    if (!cryptographer->Encrypt(new_specifics,
+                                generated_specifics.mutable_encrypted())) {
+      NOTREACHED() << "Could not encrypt data for node of type "
+                   << syncable::ModelTypeToString(type);
+      return false;
+    }
+  }
+
+  const sync_pb::EntitySpecifics& old_specifics = entry->Get(SPECIFICS);
+  if (AreSpecificsEqual(cryptographer, old_specifics, generated_specifics)) {
+    // Even if the data is the same but the old specifics are encrypted with an
+    // old key, we should go ahead and re-encrypt with the new key.
+    if ((!old_specifics.has_encrypted() &&
+         !generated_specifics.has_encrypted()) ||
+         cryptographer->CanDecryptUsingDefaultKey(old_specifics.encrypted())) {
+      VLOG(2) << "Specifics of type " << syncable::ModelTypeToString(type)
+              << " already match, dropping change.";
+      return true;
+    }
+    // TODO(zea): Add some way to keep track of how often we're reencrypting
+    // because of a passphrase change.
+  }
+
+  if (generated_specifics.has_encrypted()) {
+    // Overwrite the possibly sensitive non-specifics data.
+    entry->Put(syncable::NON_UNIQUE_NAME, kEncryptedString);
+    // For bookmarks we actually put bogus data into the unencrypted specifics,
+    // else the server will try to do it for us.
+    if (type == syncable::BOOKMARKS) {
+      sync_pb::BookmarkSpecifics* bookmark_specifics =
+          generated_specifics.MutableExtension(sync_pb::bookmark);
+      if (!entry->Get(syncable::IS_DIR))
+        bookmark_specifics->set_url(kEncryptedString);
+      bookmark_specifics->set_title(kEncryptedString);
+    }
+  }
+  entry->Put(syncable::SPECIFICS, generated_specifics);
+  syncable::MarkForSyncing(entry);
+  return true;
+}
+
+void WriteNode::SetIsFolder(bool folder) {
+  if (entry_->Get(syncable::IS_DIR) == folder)
+    return;  // Skip redundant changes.
+
+  entry_->Put(syncable::IS_DIR, folder);
+  MarkForSyncing();
+}
+
+void WriteNode::SetTitle(const std::wstring& title) {
+  std::string server_legal_name;
+  SyncAPINameToServerName(title, &server_legal_name);
+
+  string old_name = entry_->Get(syncable::NON_UNIQUE_NAME);
+
+  if (server_legal_name == old_name)
+    return;  // Skip redundant changes.
+
+  // Only set NON_UNIQUE_NAME to the title if we're not encrypted.
+  if (GetEntitySpecifics().has_encrypted())
+    entry_->Put(syncable::NON_UNIQUE_NAME, kEncryptedString);
+  else
+    entry_->Put(syncable::NON_UNIQUE_NAME, server_legal_name);
+
+  // For bookmarks, we also set the title field in the specifics.
+  // TODO(zea): refactor bookmarks to not need this functionality.
+  if (GetModelType() == syncable::BOOKMARKS) {
+    sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
+    new_value.set_title(server_legal_name);
+    SetBookmarkSpecifics(new_value);  // Does it's own encryption checking.
+  }
+
+  MarkForSyncing();
+}
+
+void WriteNode::SetURL(const GURL& url) {
+  sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
+  new_value.set_url(url.spec());
+  SetBookmarkSpecifics(new_value);
+}
+
+void WriteNode::SetAppSpecifics(
+    const sync_pb::AppSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::app)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetAutofillSpecifics(
+    const sync_pb::AutofillSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::autofill)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetAutofillProfileSpecifics(
+    const sync_pb::AutofillProfileSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::autofill_profile)->
+      CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetBookmarkSpecifics(
+    const sync_pb::BookmarkSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::bookmark)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetNigoriSpecifics(
+    const sync_pb::NigoriSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::nigori)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetPasswordSpecifics(
+    const sync_pb::PasswordSpecificsData& data) {
+  DCHECK_EQ(syncable::PASSWORDS, GetModelType());
+
+  Cryptographer* cryptographer = GetTransaction()->GetCryptographer();
+
+  // Idempotency check to prevent unnecessary syncing: if the plaintexts match
+  // and the old ciphertext is encrypted with the most current key, there's
+  // nothing to do here.  Because each encryption is seeded with a different
+  // random value, checking for equivalence post-encryption doesn't suffice.
+  const sync_pb::EncryptedData& old_ciphertext =
+      GetEntry()->Get(SPECIFICS).GetExtension(sync_pb::password).encrypted();
+  scoped_ptr<sync_pb::PasswordSpecificsData> old_plaintext(
+      DecryptPasswordSpecifics(GetEntry()->Get(SPECIFICS), cryptographer));
+  if (old_plaintext.get() &&
+      old_plaintext->SerializeAsString() == data.SerializeAsString() &&
+      cryptographer->CanDecryptUsingDefaultKey(old_ciphertext)) {
+    return;
+  }
+
+  sync_pb::PasswordSpecifics new_value;
+  if (!cryptographer->Encrypt(data, new_value.mutable_encrypted())) {
+    NOTREACHED() << "Failed to encrypt password, possibly due to sync node "
+                 << "corruption";
+    return;
+  }
+
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::password)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetThemeSpecifics(
+    const sync_pb::ThemeSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::theme)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetSessionSpecifics(
+    const sync_pb::SessionSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::session)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetEntitySpecifics(
+    const sync_pb::EntitySpecifics& new_value) {
+  syncable::ModelType new_specifics_type =
+      syncable::GetModelTypeFromSpecifics(new_value);
+  DCHECK_NE(new_specifics_type, syncable::UNSPECIFIED);
+  VLOG(1) << "Writing entity specifics of type "
+          << syncable::ModelTypeToString(new_specifics_type);
+  // GetModelType() can be unspecified if this is the first time this
+  // node is being initialized (see PutModelType()).  Otherwise, it
+  // should match |new_specifics_type|.
+  if (GetModelType() != syncable::UNSPECIFIED) {
+    DCHECK_EQ(new_specifics_type, GetModelType());
+  }
+  browser_sync::Cryptographer* cryptographer =
+      GetTransaction()->GetCryptographer();
+
+  // Preserve unknown fields.
+  const sync_pb::EntitySpecifics& old_specifics = entry_->Get(SPECIFICS);
+  sync_pb::EntitySpecifics new_specifics;
+  new_specifics.CopyFrom(new_value);
+  new_specifics.mutable_unknown_fields()->MergeFrom(
+      old_specifics.unknown_fields());
+
+  // Will update the entry if encryption was necessary.
+  if (!UpdateEntryWithEncryption(cryptographer, new_specifics, entry_)) {
+    return;
+  }
+  if (entry_->Get(SPECIFICS).has_encrypted()) {
+    // EncryptIfNecessary already updated the entry for us and marked for
+    // syncing if it was needed. Now we just make a copy of the unencrypted
+    // specifics so that if this node is updated, we do not have to decrypt the
+    // old data. Note that this only modifies the node's local data, not the
+    // entry itself.
+    SetUnencryptedSpecifics(new_value);
+  }
+
+  DCHECK_EQ(new_specifics_type, GetModelType());
+}
+
+void WriteNode::ResetFromSpecifics() {
+  SetEntitySpecifics(GetEntitySpecifics());
+}
+
+void WriteNode::SetTypedUrlSpecifics(
+    const sync_pb::TypedUrlSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::typed_url)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetExtensionSpecifics(
+    const sync_pb::ExtensionSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::extension)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetExternalId(int64 id) {
+  if (GetExternalId() != id)
+    entry_->Put(syncable::LOCAL_EXTERNAL_ID, id);
+}
+
+WriteNode::WriteNode(WriteTransaction* transaction)
+    : entry_(NULL), transaction_(transaction) {
+  DCHECK(transaction);
+}
+
+WriteNode::~WriteNode() {
+  delete entry_;
+}
+
+// Find an existing node matching the ID |id|, and bind this WriteNode to it.
+// Return true on success.
+bool WriteNode::InitByIdLookup(int64 id) {
+  DCHECK(!entry_) << "Init called twice";
+  DCHECK_NE(id, kInvalidId);
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_HANDLE, id);
+  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
+          DecryptIfNecessary());
+}
+
+// Find a node by client tag, and bind this WriteNode to it.
+// Return true if the write node was found, and was not deleted.
+// Undeleting a deleted node is possible by ClientTag.
+bool WriteNode::InitByClientTagLookup(syncable::ModelType model_type,
+                                      const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+
+  const std::string hash = GenerateSyncableHash(model_type, tag);
+
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_CLIENT_TAG, hash);
+  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
+          DecryptIfNecessary());
+}
+
+bool WriteNode::InitByTagLookup(const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_SERVER_TAG, tag);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  DCHECK_EQ(syncable::NIGORI, model_type);
+  return true;
+}
+
+void WriteNode::PutModelType(syncable::ModelType model_type) {
+  // Set an empty specifics of the appropriate datatype.  The presence
+  // of the specific extension will identify the model type.
+  DCHECK(GetModelType() == model_type ||
+         GetModelType() == syncable::UNSPECIFIED);  // Immutable once set.
+
+  sync_pb::EntitySpecifics specifics;
+  syncable::AddDefaultExtensionValue(model_type, &specifics);
+  SetEntitySpecifics(specifics);
+}
+
+// Create a new node with default properties, and bind this WriteNode to it.
+// Return true on success.
+bool WriteNode::InitByCreation(syncable::ModelType model_type,
+                               const BaseNode& parent,
+                               const BaseNode* predecessor) {
+  DCHECK(!entry_) << "Init called twice";
+  // |predecessor| must be a child of |parent| or NULL.
+  if (predecessor && predecessor->GetParentId() != parent.GetId()) {
+    DCHECK(false);
+    return false;
+  }
+
+  syncable::Id parent_id = parent.GetEntry()->Get(syncable::ID);
+
+  // Start out with a dummy name.  We expect
+  // the caller to set a meaningful name after creation.
+  string dummy(kDefaultNameForNewNodes);
+
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::CREATE, parent_id, dummy);
+
+  if (!entry_->good())
+    return false;
+
+  // Entries are untitled folders by default.
+  entry_->Put(syncable::IS_DIR, true);
+
+  PutModelType(model_type);
+
+  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
+  PutPredecessor(predecessor);
+
+  return true;
+}
+
+// Create a new node with default properties and a client defined unique tag,
+// and bind this WriteNode to it.
+// Return true on success. If the tag exists in the database, then
+// we will attempt to undelete the node.
+// TODO(chron): Code datatype into hash tag.
+// TODO(chron): Is model type ever lost?
+bool WriteNode::InitUniqueByCreation(syncable::ModelType model_type,
+                                     const BaseNode& parent,
+                                     const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+
+  const std::string hash = GenerateSyncableHash(model_type, tag);
+
+  syncable::Id parent_id = parent.GetEntry()->Get(syncable::ID);
+
+  // Start out with a dummy name.  We expect
+  // the caller to set a meaningful name after creation.
+  string dummy(kDefaultNameForNewNodes);
+
+  // Check if we have this locally and need to undelete it.
+  scoped_ptr<syncable::MutableEntry> existing_entry(
+      new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                 syncable::GET_BY_CLIENT_TAG, hash));
+
+  if (existing_entry->good()) {
+    if (existing_entry->Get(syncable::IS_DEL)) {
+      // Rules for undelete:
+      // BASE_VERSION: Must keep the same.
+      // ID: Essential to keep the same.
+      // META_HANDLE: Must be the same, so we can't "split" the entry.
+      // IS_DEL: Must be set to false, will cause reindexing.
+      //         This one is weird because IS_DEL is true for "update only"
+      //         items. It should be OK to undelete an update only.
+      // MTIME/CTIME: Seems reasonable to just leave them alone.
+      // IS_UNSYNCED: Must set this to true or face database insurrection.
+      //              We do this below this block.
+      // IS_UNAPPLIED_UPDATE: Either keep it the same or also set BASE_VERSION
+      //                      to SERVER_VERSION. We keep it the same here.
+      // IS_DIR: We'll leave it the same.
+      // SPECIFICS: Reset it.
+
+      existing_entry->Put(syncable::IS_DEL, false);
+
+      // Client tags are immutable and must be paired with the ID.
+      // If a server update comes down with an ID and client tag combo,
+      // and it already exists, always overwrite it and store only one copy.
+      // We have to undelete entries because we can't disassociate IDs from
+      // tags and updates.
+
+      existing_entry->Put(syncable::NON_UNIQUE_NAME, dummy);
+      existing_entry->Put(syncable::PARENT_ID, parent_id);
+      entry_ = existing_entry.release();
+    } else {
+      return false;
+    }
+  } else {
+    entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                        syncable::CREATE, parent_id, dummy);
+    if (!entry_->good()) {
+      return false;
+    }
+
+    // Only set IS_DIR for new entries. Don't bitflip undeleted ones.
+    entry_->Put(syncable::UNIQUE_CLIENT_TAG, hash);
+  }
+
+  // We don't support directory and tag combinations.
+  entry_->Put(syncable::IS_DIR, false);
+
+  // Will clear specifics data.
+  PutModelType(model_type);
+
+  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
+  PutPredecessor(NULL);
+
+  return true;
+}
+
+bool WriteNode::SetPosition(const BaseNode& new_parent,
+                            const BaseNode* predecessor) {
+  // |predecessor| must be a child of |new_parent| or NULL.
+  if (predecessor && predecessor->GetParentId() != new_parent.GetId()) {
+    DCHECK(false);
+    return false;
+  }
+
+  syncable::Id new_parent_id = new_parent.GetEntry()->Get(syncable::ID);
+
+  // Filter out redundant changes if both the parent and the predecessor match.
+  if (new_parent_id == entry_->Get(syncable::PARENT_ID)) {
+    const syncable::Id& old = entry_->Get(syncable::PREV_ID);
+    if ((!predecessor && old.IsRoot()) ||
+        (predecessor && (old == predecessor->GetEntry()->Get(syncable::ID)))) {
+      return true;
+    }
+  }
+
+  // Atomically change the parent. This will fail if it would
+  // introduce a cycle in the hierarchy.
+  if (!entry_->Put(syncable::PARENT_ID, new_parent_id))
+    return false;
+
+  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
+  PutPredecessor(predecessor);
+
+  return true;
+}
+
+const syncable::Entry* WriteNode::GetEntry() const {
+  return entry_;
+}
+
+const BaseTransaction* WriteNode::GetTransaction() const {
+  return transaction_;
+}
+
+void WriteNode::Remove() {
+  entry_->Put(syncable::IS_DEL, true);
+  MarkForSyncing();
+}
+
+void WriteNode::PutPredecessor(const BaseNode* predecessor) {
+  syncable::Id predecessor_id = predecessor ?
+      predecessor->GetEntry()->Get(syncable::ID) : syncable::Id();
+  entry_->PutPredecessor(predecessor_id);
+  // Mark this entry as unsynced, to wake up the syncer.
+  MarkForSyncing();
+}
+
+void WriteNode::SetFaviconBytes(const vector<unsigned char>& bytes) {
+  sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
+  new_value.set_favicon(bytes.empty() ? NULL : &bytes[0], bytes.size());
+  SetBookmarkSpecifics(new_value);
+}
+
+void WriteNode::MarkForSyncing() {
+  syncable::MarkForSyncing(entry_);
+}
+
+} // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/write_node.h b/chrome/browser/sync/internal_api/write_node.h
new file mode 100644
index 0000000..75e4f21
--- /dev/null
+++ b/chrome/browser/sync/internal_api/write_node.h
@@ -0,0 +1,193 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_NODE_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_NODE_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "chrome/browser/sync/internal_api/base_node.h"
+#include "chrome/browser/sync/syncable/model_type.h"
+
+namespace browser_sync {
+class Cryptographer;
+}
+
+namespace syncable {
+class Entry;
+class MutableEntry;
+}
+
+namespace sync_pb {
+class AppSpecifics;
+class AutofillSpecifics;
+class AutofillProfileSpecifics;
+class BookmarkSpecifics;
+class EntitySpecifics;
+class ExtensionSpecifics;
+class SessionSpecifics;
+class NigoriSpecifics;
+class PreferenceSpecifics;
+class PasswordSpecificsData;
+class ThemeSpecifics;
+class TypedUrlSpecifics;
+}
+
+namespace sync_api {
+
+class WriteTransaction;
+
+// WriteNode extends BaseNode to add mutation, and wraps
+// syncable::MutableEntry. A WriteTransaction is needed to create a WriteNode.
+class WriteNode : public BaseNode {
+ public:
+  // Create a WriteNode using the given transaction.
+  explicit WriteNode(WriteTransaction* transaction);
+  virtual ~WriteNode();
+
+  // A client must use one (and only one) of the following Init variants to
+  // populate the node.
+
+  // BaseNode implementation.
+  virtual bool InitByIdLookup(int64 id);
+  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
+      const std::string& tag);
+
+  // Create a new node with the specified parent and predecessor.  |model_type|
+  // dictates the type of the item, and controls which EntitySpecifics proto
+  // extension can be used with this item.  Use a NULL |predecessor|
+  // to indicate that this is to be the first child.
+  // |predecessor| must be a child of |new_parent| or NULL. Returns false on
+  // failure.
+  bool InitByCreation(syncable::ModelType model_type,
+                      const BaseNode& parent,
+                      const BaseNode* predecessor);
+
+  // Create nodes using this function if they're unique items that
+  // you want to fetch using client_tag. Note that the behavior of these
+  // items is slightly different than that of normal items.
+  // Most importantly, if it exists locally, this function will
+  // actually undelete it
+  // Client unique tagged nodes must NOT be folders.
+  bool InitUniqueByCreation(syncable::ModelType model_type,
+                            const BaseNode& parent,
+                            const std::string& client_tag);
+
+  // Each server-created permanent node is tagged with a unique string.
+  // Look up the node with the particular tag.  If it does not exist,
+  // return false.
+  bool InitByTagLookup(const std::string& tag);
+
+  // These Set() functions correspond to the Get() functions of BaseNode.
+  void SetIsFolder(bool folder);
+  void SetTitle(const std::wstring& title);
+
+  // External ID is a client-only field, so setting it doesn't cause the item to
+  // be synced again.
+  void SetExternalId(int64 external_id);
+
+  // Remove this node and its children.
+  void Remove();
+
+  // Set a new parent and position.  Position is specified by |predecessor|; if
+  // it is NULL, the node is moved to the first position.  |predecessor| must
+  // be a child of |new_parent| or NULL.  Returns false on failure..
+  bool SetPosition(const BaseNode& new_parent, const BaseNode* predecessor);
+
+  // Set the bookmark specifics (url and favicon).
+  // Should only be called if GetModelType() == BOOKMARK.
+  void SetBookmarkSpecifics(const sync_pb::BookmarkSpecifics& specifics);
+
+  // Legacy, bookmark-specific setters that wrap SetBookmarkSpecifics() above.
+  // Should only be called if GetModelType() == BOOKMARK.
+  // TODO(ncarter): Remove these two datatype-specific accessors.
+  void SetURL(const GURL& url);
+  void SetFaviconBytes(const std::vector<unsigned char>& bytes);
+
+  // Generic set specifics method. Will extract the model type from |specifics|.
+  void SetEntitySpecifics(const sync_pb::EntitySpecifics& specifics);
+
+  // Resets the EntitySpecifics for this node based on the unencrypted data.
+  // Will encrypt if necessary.
+  void ResetFromSpecifics();
+
+  // TODO(sync): Remove the setters below when the corresponding data
+  // types are ported to the new sync service API.
+
+  // Set the app specifics (id, update url, enabled state, etc).
+  // Should only be called if GetModelType() == APPS.
+  void SetAppSpecifics(const sync_pb::AppSpecifics& specifics);
+
+  // Set the autofill specifics (name and value).
+  // Should only be called if GetModelType() == AUTOFILL.
+  void SetAutofillSpecifics(const sync_pb::AutofillSpecifics& specifics);
+
+  void SetAutofillProfileSpecifics(
+      const sync_pb::AutofillProfileSpecifics& specifics);
+
+  // Set the nigori specifics.
+  // Should only be called if GetModelType() == NIGORI.
+  void SetNigoriSpecifics(const sync_pb::NigoriSpecifics& specifics);
+
+  // Set the password specifics.
+  // Should only be called if GetModelType() == PASSWORD.
+  void SetPasswordSpecifics(const sync_pb::PasswordSpecificsData& specifics);
+
+  // Set the theme specifics (name and value).
+  // Should only be called if GetModelType() == THEME.
+  void SetThemeSpecifics(const sync_pb::ThemeSpecifics& specifics);
+
+  // Set the typed_url specifics (url, title, typed_count, etc).
+  // Should only be called if GetModelType() == TYPED_URLS.
+  void SetTypedUrlSpecifics(const sync_pb::TypedUrlSpecifics& specifics);
+
+  // Set the extension specifics (id, update url, enabled state, etc).
+  // Should only be called if GetModelType() == EXTENSIONS.
+  void SetExtensionSpecifics(const sync_pb::ExtensionSpecifics& specifics);
+
+  // Set the session specifics (windows, tabs, navigations etc.).
+  // Should only be called if GetModelType() == SESSIONS.
+  void SetSessionSpecifics(const sync_pb::SessionSpecifics& specifics);
+
+  // Stores |new_specifics| into |entry|, encrypting if necessary.
+  // Returns false if an error encrypting occurred (does not modify |entry|).
+  // Note: gracefully handles new_specifics aliasing with entry->Get(SPECIFICS).
+  static bool UpdateEntryWithEncryption(
+      browser_sync::Cryptographer* cryptographer,
+      const sync_pb::EntitySpecifics& new_specifics,
+      syncable::MutableEntry* entry);
+
+  // Implementation of BaseNode's abstract virtual accessors.
+  virtual const syncable::Entry* GetEntry() const;
+
+  virtual const BaseTransaction* GetTransaction() const;
+
+ private:
+  void* operator new(size_t size);  // Node is meant for stack use only.
+
+  // Helper to set model type. This will clear any specifics data.
+  void PutModelType(syncable::ModelType model_type);
+
+  // Helper to set the previous node.
+  void PutPredecessor(const BaseNode* predecessor);
+
+  // Sets IS_UNSYNCED and SYNCING to ensure this entry is considered in an
+  // upcoming commit pass.
+  void MarkForSyncing();
+
+  // The underlying syncable object which this class wraps.
+  syncable::MutableEntry* entry_;
+
+  // The sync API transaction that is the parent of this node.
+  WriteTransaction* transaction_;
+
+  DISALLOW_COPY_AND_ASSIGN(WriteNode);
+};
+
+}  // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_NODE_H_
diff --git a/chrome/browser/sync/internal_api/write_transaction.cc b/chrome/browser/sync/internal_api/write_transaction.cc
new file mode 100644
index 0000000..1bed02b
--- /dev/null
+++ b/chrome/browser/sync/internal_api/write_transaction.cc
@@ -0,0 +1,29 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/sync/internal_api/write_transaction.h"
+
+#include "chrome/browser/sync/syncable/syncable.h"
+
+namespace sync_api {
+
+//////////////////////////////////////////////////////////////////////////
+// WriteTransaction member definitions
+WriteTransaction::WriteTransaction(const tracked_objects::Location& from_here,
+                                   UserShare* share)
+    : BaseTransaction(share),
+      transaction_(NULL) {
+  transaction_ = new syncable::WriteTransaction(from_here, syncable::SYNCAPI,
+                                                GetLookup());
+}
+
+WriteTransaction::~WriteTransaction() {
+  delete transaction_;
+}
+
+syncable::BaseTransaction* WriteTransaction::GetWrappedTrans() const {
+  return transaction_;
+}
+
+} // namespace sync_api
diff --git a/chrome/browser/sync/internal_api/write_transaction.h b/chrome/browser/sync/internal_api/write_transaction.h
new file mode 100644
index 0000000..e90abc7
--- /dev/null
+++ b/chrome/browser/sync/internal_api/write_transaction.h
@@ -0,0 +1,56 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_TRANSACTION_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_TRANSACTION_H_
+
+#include "base/basictypes.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+
+namespace syncable {
+class BaseTransaction;
+class WriteTransaction;
+}  // namespace syncable
+
+namespace tracked_objects {
+class Location;
+}  // namespace tracked_objects
+
+namespace sync_api {
+
+// Sync API's WriteTransaction is a read/write BaseTransaction.  It wraps
+// a syncable::WriteTransaction.
+//
+// NOTE: Only a single model type can be mutated for a given
+// WriteTransaction.
+class WriteTransaction : public BaseTransaction {
+ public:
+  // Start a new read/write transaction.
+  WriteTransaction(const tracked_objects::Location& from_here,
+                   UserShare* share);
+  virtual ~WriteTransaction();
+
+  // Provide access to the syncable.h transaction from the API WriteNode.
+  virtual syncable::BaseTransaction* GetWrappedTrans() const;
+  syncable::WriteTransaction* GetWrappedWriteTrans() { return transaction_; }
+
+ protected:
+  WriteTransaction() {}
+
+  void SetTransaction(syncable::WriteTransaction* trans) {
+      transaction_ = trans;
+  }
+
+ private:
+  void* operator new(size_t size);  // Transaction is meant for stack use only.
+
+  // The underlying syncable object which this class wraps.
+  syncable::WriteTransaction* transaction_;
+
+  DISALLOW_COPY_AND_ASSIGN(WriteTransaction);
+};
+
+} // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_TRANSACTION_H_
diff --git a/chrome/browser/sync/js/DEPS b/chrome/browser/sync/js/DEPS
index 0123cb9..3b29013 100644
--- a/chrome/browser/sync/js/DEPS
+++ b/chrome/browser/sync/js/DEPS
@@ -4,9 +4,7 @@ include_rules = [
 
   "+chrome/browser/sync/js",
 
-  # The following should live in their own "includes" directory(ies).
-  # Bug 19878.
-  "+chrome/browser/sync/engine/syncapi.h",
+  "+chrome/browser/sync/internal_api",
   "+chrome/browser/sync/sessions/session_state.h",
   "+chrome/browser/sync/syncable/model_type.h",
   "+chrome/browser/sync/syncable/transaction_observer.h",
diff --git a/chrome/browser/sync/js/js_sync_manager_observer.h b/chrome/browser/sync/js/js_sync_manager_observer.h
index cc7c8c0..a4b364a 100644
--- a/chrome/browser/sync/js/js_sync_manager_observer.h
+++ b/chrome/browser/sync/js/js_sync_manager_observer.h
@@ -9,7 +9,7 @@
 #include <string>
 
 #include "base/basictypes.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/weak_handle.h"
 
 namespace tracked_objects {
diff --git a/chrome/browser/sync/js/js_sync_manager_observer_unittest.cc b/chrome/browser/sync/js/js_sync_manager_observer_unittest.cc
index a29b9aa..4ffd253 100644
--- a/chrome/browser/sync/js/js_sync_manager_observer_unittest.cc
+++ b/chrome/browser/sync/js/js_sync_manager_observer_unittest.cc
@@ -10,7 +10,10 @@
 #include "base/message_loop.h"
 #include "base/tracked.h"
 #include "base/values.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/js/js_arg_list.h"
 #include "chrome/browser/sync/js/js_event_details.h"
 #include "chrome/browser/sync/js/js_test_util.h"
diff --git a/chrome/browser/sync/notifier/DEPS b/chrome/browser/sync/notifier/DEPS
index ab0257a..96351bd 100644
--- a/chrome/browser/sync/notifier/DEPS
+++ b/chrome/browser/sync/notifier/DEPS
@@ -16,4 +16,6 @@ include_rules = [
   "+talk/base",
   # sync_notifier depends on the xmpp part of libjingle.
   "+talk/xmpp",
+
+  "-chrome/browser/sync/internal_api",
 ]
diff --git a/chrome/browser/sync/profile_sync_factory_impl_unittest.cc b/chrome/browser/sync/profile_sync_factory_impl_unittest.cc
index 953ed64..414e3a9 100644
--- a/chrome/browser/sync/profile_sync_factory_impl_unittest.cc
+++ b/chrome/browser/sync/profile_sync_factory_impl_unittest.cc
@@ -4,19 +4,18 @@
 
 #include <vector>
 
-#include "testing/gtest/include/gtest/gtest.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/data_type_controller.h"
-#include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_factory_impl.h"
+#include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/testing_browser_process_test.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/browser/browser_thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
 
 using browser_sync::DataTypeController;
 
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 6f3d07f..70da3a1 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -27,11 +27,11 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/backend_migrator.h"
 #include "chrome/browser/sync/engine/configure_reason.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/change_processor.h"
 #include "chrome/browser/sync/glue/data_type_controller.h"
 #include "chrome/browser/sync/glue/data_type_manager.h"
 #include "chrome/browser/sync/glue/session_data_type_controller.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/js/js_arg_list.h"
 #include "chrome/browser/sync/js/js_event_details.h"
 #include "chrome/browser/sync/profile_sync_factory.h"
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index 558c548..d32b737 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -23,10 +23,11 @@
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/glue/data_type_controller.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
 #include "chrome/browser/sync/profile_sync_service_observer.h"
+#include "chrome/browser/sync/syncable/model_type.h"
 #include "chrome/browser/sync/sync_js_controller.h"
 #include "chrome/browser/sync/sync_setup_wizard.h"
-#include "chrome/browser/sync/syncable/model_type.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 #include "chrome/common/net/gaia/google_service_auth_error.h"
 #include "content/common/content_notification_types.h"
diff --git a/chrome/browser/sync/profile_sync_service_autofill_unittest.cc b/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
index f00e7ba..df1fbfd 100644
--- a/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
@@ -21,7 +21,6 @@
 #include "chrome/browser/autofill/autofill_common_test.h"
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
 #include "chrome/browser/sync/engine/model_changing_syncer_command.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/autofill_change_processor.h"
 #include "chrome/browser/sync/glue/autofill_data_type_controller.h"
 #include "chrome/browser/sync/glue/autofill_model_associator.h"
@@ -29,6 +28,10 @@
 #include "chrome/browser/sync/glue/autofill_profile_data_type_controller.h"
 #include "chrome/browser/sync/glue/autofill_profile_model_associator.h"
 #include "chrome/browser/sync/glue/data_type_controller.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_test_util.h"
diff --git a/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc b/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
index 790aaae..2f1e2ad 100644
--- a/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
@@ -22,9 +22,13 @@
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
 #include "chrome/browser/sync/api/sync_error.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/bookmark_change_processor.h"
 #include "chrome/browser/sync/glue/bookmark_model_associator.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/testing_browser_process_test.h"
diff --git a/chrome/browser/sync/profile_sync_service_password_unittest.cc b/chrome/browser/sync/profile_sync_service_password_unittest.cc
index b61c860..175018a 100644
--- a/chrome/browser/sync/profile_sync_service_password_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_password_unittest.cc
@@ -15,10 +15,13 @@
 #include "chrome/browser/password_manager/password_store.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/password_change_processor.h"
 #include "chrome/browser/sync/glue/password_data_type_controller.h"
 #include "chrome/browser/sync/glue/password_model_associator.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_factory.h"
 #include "chrome/browser/sync/profile_sync_factory_mock.h"
 #include "chrome/browser/sync/profile_sync_service.h"
diff --git a/chrome/browser/sync/profile_sync_service_preference_unittest.cc b/chrome/browser/sync/profile_sync_service_preference_unittest.cc
index 41c6ba7..c577462 100644
--- a/chrome/browser/sync/profile_sync_service_preference_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_preference_unittest.cc
@@ -14,11 +14,15 @@
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
 #include "chrome/browser/sync/api/sync_data.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/generic_change_processor.h"
 #include "chrome/browser/sync/glue/preference_data_type_controller.h"
-#include "chrome/browser/sync/glue/sync_backend_host.h"
 #include "chrome/browser/sync/glue/syncable_service_adapter.h"
+#include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_test_util.h"
 #include "chrome/browser/sync/protocol/preference_specifics.pb.h"
 #include "chrome/browser/sync/syncable/model_type.h"
diff --git a/chrome/browser/sync/profile_sync_service_session_unittest.cc b/chrome/browser/sync/profile_sync_service_session_unittest.cc
index 509dfe1..fa2a5ec 100644
--- a/chrome/browser/sync/profile_sync_service_session_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_session_unittest.cc
@@ -11,15 +11,18 @@
 #include "base/stl_util.h"
 #include "base/task.h"
 #include "base/tracked.h"
-#include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_service_factory.h"
+#include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_service_test_helper.h"
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/session_change_processor.h"
 #include "chrome/browser/sync/glue/session_data_type_controller.h"
 #include "chrome/browser/sync/glue/session_model_associator.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/sync_manager.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_factory_mock.h"
 #include "chrome/browser/sync/profile_sync_test_util.h"
 #include "chrome/browser/sync/protocol/session_specifics.pb.h"
diff --git a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
index d7dfe13..432aeb4 100644
--- a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
@@ -16,12 +16,15 @@
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
 #include "chrome/browser/sync/glue/sync_backend_host_mock.h"
 #include "chrome/browser/sync/glue/typed_url_change_processor.h"
 #include "chrome/browser/sync/glue/typed_url_data_type_controller.h"
 #include "chrome/browser/sync/glue/typed_url_model_associator.h"
+#include "chrome/browser/sync/internal_api/read_node.h"
+#include "chrome/browser/sync/internal_api/read_transaction.h"
+#include "chrome/browser/sync/internal_api/write_node.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/profile_sync_factory.h"
 #include "chrome/browser/sync/profile_sync_factory_mock.h"
 #include "chrome/browser/sync/profile_sync_service.h"
diff --git a/chrome/browser/sync/protocol/DEPS b/chrome/browser/sync/protocol/DEPS
index 7f28a59..fdf9fa3 100644
--- a/chrome/browser/sync/protocol/DEPS
+++ b/chrome/browser/sync/protocol/DEPS
@@ -2,5 +2,7 @@ include_rules = [
   "-chrome",
   "+chrome/browser/sync/protocol",
   "+chrome/browser/sync/syncable/model_type.h",
+
+  "-chrome/browser/sync/internal_api",
 ]
 
diff --git a/chrome/browser/sync/sessions/DEPS b/chrome/browser/sync/sessions/DEPS
index cb4f078..0d7660a 100644
--- a/chrome/browser/sync/sessions/DEPS
+++ b/chrome/browser/sync/sessions/DEPS
@@ -8,5 +8,7 @@ include_rules = [
   "+chrome/browser/sync/sessions",
   "+chrome/browser/sync/syncable",
   "+chrome/browser/sync/util",
+
+  "-chrome/browser/sync/internal_api",
 ]
 
diff --git a/chrome/browser/sync/sync_setup_wizard_unittest.cc b/chrome/browser/sync/sync_setup_wizard_unittest.cc
index 9611dc7..3b2a86e 100644
--- a/chrome/browser/sync/sync_setup_wizard_unittest.cc
+++ b/chrome/browser/sync/sync_setup_wizard_unittest.cc
@@ -9,7 +9,6 @@
 #include "base/stl_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/prefs/pref_service.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/profile_sync_factory_mock.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/signin_manager.h"
diff --git a/chrome/browser/sync/syncable/DEPS b/chrome/browser/sync/syncable/DEPS
index 710d381..032cd30 100644
--- a/chrome/browser/sync/syncable/DEPS
+++ b/chrome/browser/sync/syncable/DEPS
@@ -16,5 +16,7 @@ include_rules = [
 
   "+chrome/common/random.h",
   "+chrome/common/sqlite_utils.h",
+
+  "-chrome/browser/sync/internal_api",
 ]
 
diff --git a/chrome/browser/sync/syncable/model_type_payload_map.cc b/chrome/browser/sync/syncable/model_type_payload_map.cc
index 2507a2b..288d8ff 100644
--- a/chrome/browser/sync/syncable/model_type_payload_map.cc
+++ b/chrome/browser/sync/syncable/model_type_payload_map.cc
@@ -7,7 +7,7 @@
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 
 #include "base/json/json_writer.h"
-#include "base/scoped_ptr.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 
 using browser_sync::ModelSafeRoutingInfo;
diff --git a/chrome/browser/sync/syncable/syncable.cc b/chrome/browser/sync/syncable/syncable.cc
index cf30b99..4ece5bd 100644
--- a/chrome/browser/sync/syncable/syncable.cc
+++ b/chrome/browser/sync/syncable/syncable.cc
@@ -27,14 +27,14 @@
 #include <set>
 #include <string>
 
-#include "base/hash_tables.h"
 #include "base/file_util.h"
+#include "base/hash_tables.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/perftimer.h"
+#include "base/stl_util.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
-#include "base/stl_util.h"
 #include "base/time.h"
 #include "base/tracked.h"
 #include "base/utf_string_conversions.h"
@@ -45,10 +45,10 @@
 #include "chrome/browser/sync/syncable/directory_change_delegate.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/browser/sync/syncable/model_type.h"
-#include "chrome/browser/sync/syncable/syncable-inl.h"
 #include "chrome/browser/sync/syncable/syncable_changes_version.h"
 #include "chrome/browser/sync/syncable/syncable_columns.h"
 #include "chrome/browser/sync/syncable/syncable_enum_conversions.h"
+#include "chrome/browser/sync/syncable/syncable-inl.h"
 #include "chrome/browser/sync/syncable/transaction_observer.h"
 #include "chrome/browser/sync/util/logging.h"
 #include "net/base/escape.h"
diff --git a/chrome/browser/sync/test_profile_sync_service.cc b/chrome/browser/sync/test_profile_sync_service.cc
index 22737a1..4fd70fa 100644
--- a/chrome/browser/sync/test_profile_sync_service.cc
+++ b/chrome/browser/sync/test_profile_sync_service.cc
@@ -5,9 +5,9 @@
 #include "chrome/browser/sync/test_profile_sync_service.h"
 
 #include "chrome/browser/sync/abstract_profile_sync_service_test.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/data_type_controller.h"
 #include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/browser/sync/internal_api/user_share.h"
 #include "chrome/browser/sync/js/js_reply_handler.h"
 #include "chrome/browser/sync/profile_sync_factory.h"
 #include "chrome/browser/sync/sessions/session_state.h"
diff --git a/chrome/browser/ui/webui/ntp/foreign_session_handler.cc b/chrome/browser/ui/webui/ntp/foreign_session_handler.cc
index e0e968b..cbab342 100644
--- a/chrome/browser/ui/webui/ntp/foreign_session_handler.cc
+++ b/chrome/browser/ui/webui/ntp/foreign_session_handler.cc
@@ -13,13 +13,12 @@
 #include "base/values.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_restore.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/ui/webui/ntp/new_tab_ui.h"
 #include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/url_constants.h"
 #include "content/common/notification_details.h"
 #include "content/common/notification_service.h"
-#include "chrome/common/url_constants.h"
 
 namespace browser_sync {
 
diff --git a/chrome/browser/ui/webui/sessions_ui.cc b/chrome/browser/ui/webui/sessions_ui.cc
index 9bbabbd..4522ddf 100644
--- a/chrome/browser/ui/webui/sessions_ui.cc
+++ b/chrome/browser/ui/webui/sessions_ui.cc
@@ -7,7 +7,6 @@
 #include <algorithm>
 
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/glue/session_model_associator.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/ui/webui/chrome_url_data_manager.h"
@@ -26,7 +25,6 @@
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
-
 namespace {
 
 ChromeWebUIDataSource* CreateSessionsUIHTMLSource() {
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index dd4d302..9b220b3 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -505,11 +505,27 @@
       'target_name': 'syncapi_core',
       'type': 'static_library',
       'sources': [
+        'browser/sync/engine/configure_reason.h'
         'browser/sync/engine/http_post_provider_factory.h',
         'browser/sync/engine/http_post_provider_interface.h',
-        'browser/sync/engine/syncapi.cc',
-        'browser/sync/engine/syncapi.h',
-        'browser/sync/engine/configure_reason.h'
+        'browser/sync/engine/syncapi_internal.cc',
+        'browser/sync/engine/syncapi_internal.h',
+        'browser/sync/internal_api/base_node.cc',
+        'browser/sync/internal_api/base_node.h',
+        'browser/sync/internal_api/base_transaction.cc',
+        'browser/sync/internal_api/base_transaction.h',
+        'browser/sync/internal_api/read_node.cc',
+        'browser/sync/internal_api/read_node.h',
+        'browser/sync/internal_api/read_transaction.cc',
+        'browser/sync/internal_api/read_transaction.h',
+        'browser/sync/internal_api/sync_manager.cc',
+        'browser/sync/internal_api/sync_manager.h',
+        'browser/sync/internal_api/user_share.cc',
+        'browser/sync/internal_api/user_share.h',
+        'browser/sync/internal_api/write_node.cc',
+        'browser/sync/internal_api/write_node.h',
+        'browser/sync/internal_api/write_transaction.cc',
+        'browser/sync/internal_api/write_transaction.h',
       ],
       'include_dirs': [
         '..',
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 0fe71e1..91d2f10 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1658,8 +1658,8 @@
         'browser/sync/abstract_profile_sync_service_test.cc',
         'browser/sync/abstract_profile_sync_service_test.h',
         'browser/sync/backend_migrator_unittest.cc',
-        'browser/sync/engine/read_node_mock.cc',
-        'browser/sync/engine/read_node_mock.h',
+        'browser/sync/internal_api/read_node_mock.cc',
+        'browser/sync/internal_api/read_node_mock.h',
         'browser/sync/glue/autofill_data_type_controller_unittest.cc',
         'browser/sync/glue/autofill_model_associator_unittest.cc',
         'browser/sync/glue/autofill_profile_model_associator_unittest.cc',
@@ -3138,14 +3138,14 @@
         'browser/sync/engine/mock_model_safe_workers.h',
         'browser/sync/engine/nigori_util_unittest.cc',
         'browser/sync/engine/process_commit_response_command_unittest.cc',
-        'browser/sync/engine/syncapi_unittest.cc',
         'browser/sync/engine/syncer_proto_util_unittest.cc',
         'browser/sync/engine/sync_scheduler_unittest.cc',
         'browser/sync/engine/sync_scheduler_whitebox_unittest.cc',
         'browser/sync/engine/syncer_unittest.cc',
         'browser/sync/engine/syncproto_unittest.cc',
-        'browser/sync/engine/syncapi_mock.h',
         'browser/sync/engine/verify_updates_command_unittest.cc',
+        'browser/sync/internal_api/syncapi_mock.h',
+        'browser/sync/internal_api/syncapi_unittest.cc',
         'browser/sync/js/js_arg_list_unittest.cc',
         'browser/sync/js/js_event_details_unittest.cc',
         'browser/sync/js/js_sync_manager_observer_unittest.cc',
diff --git a/chrome/test/sync/engine/test_user_share.h b/chrome/test/sync/engine/test_user_share.h
index 00d73d1..969decd 100644
--- a/chrome/test/sync/engine/test_user_share.h
+++ b/chrome/test/sync/engine/test_user_share.h
@@ -32,7 +32,7 @@
 #pragma once
 
 #include "base/basictypes.h"
-#include "chrome/browser/sync/engine/syncapi.h"
+#include "chrome/browser/sync/internal_api/user_share.h"
 #include "chrome/test/sync/engine/test_directory_setter_upper.h"
 
 namespace browser_sync {