Support for multiple sync ModelSafeWorkers.

- Introduce an equivalence class enum to group sync model types that live on the same
chrome native model together.
- Remove ModelSafeWorkerBridge as it is no longer needed.
- Rename BookmarkModelWorker -> UIModelWorker, and make it use the new stuff.
- Allow syncable entries belonging to an "unsynced" model type to be just
processed "passively" from
the SyncerThread (rather than dispatching), and allow this to change as a result
of enable/disabling.
- Experimenting with a way to complete issue 31909 (the CLASS_UNASSOCIATED
stuff).

BUG=31925,31911,31909
Review URL: http://codereview.chromium.org/553015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@36835 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 67 insertions, 10 deletions

diff --git a/chrome/browser/sync/sessions/sync_session.cc b/chrome/browser/sync/sessions/sync_session.cc
index 296c532..5a0a3e8 100644
--- a/chrome/browser/sync/sessions/sync_session.cc
+++ b/chrome/browser/sync/sessions/sync_session.cc
@@ -14,6 +14,23 @@ SyncSession::SyncSession(SyncSessionContext* context, Delegate* delegate)
       write_transaction_(NULL),
       delegate_(delegate),
       auth_failure_occurred_(false) {
+
+  std::vector<ModelSafeWorker*>* s =
+      const_cast<std::vector<ModelSafeWorker*>* >(&workers_);
+  context_->registrar()->GetWorkers(s);
+
+  // TODO(tim): Use ModelSafeRoutingInfo to silo parts of the session status by
+  // ModelSafeGroup;
+  // e.g. have a map<class, commit_ids>, map<class, ConflictProgress> etc.
+  // The routing will be used to map multiple model types into the right silo.
+  // The routing info can't change throughout a session, so we're assured that
+  // (for example) commit_ids for syncable::AUTOFILL items that were being
+  // processed as part of the GROUP_PASSIVE run (because they weren't being
+  // synced) *continue* to be for this whole session, even though the
+  // ModelSafeWorkerRegistrar may be configured to route syncable::AUTOFILL to
+  // GROUP_DB now.
+  group_restriction_in_effect_ = false;
+  group_restriction_ = GROUP_PASSIVE;
 }
 
 SyncSessionSnapshot SyncSession::TakeSnapshot() const {
diff --git a/chrome/browser/sync/sessions/sync_session.h b/chrome/browser/sync/sessions/sync_session.h
index 4f44596..3d990a7 100644
--- a/chrome/browser/sync/sessions/sync_session.h
+++ b/chrome/browser/sync/sessions/sync_session.h
@@ -15,6 +15,7 @@
 #define CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_H_
 
 #include <string>
+#include <vector>
 
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
@@ -29,6 +30,8 @@ class WriteTransaction;
 }
 
 namespace browser_sync {
+class ModelSafeWorker;
+
 namespace sessions {
 
 class SyncSession {
@@ -99,11 +102,14 @@ class SyncSession {
     source_ = source;
   }
 
+  const std::vector<ModelSafeWorker*>& workers() const { return workers_; }
+
  private:
   // Extend the encapsulation boundary to utilities for internal member
   // assignments. This way, the scope of these actions is explicit, they can't
   // be overridden, and assigning is always accompanied by unassigning.
   friend class ScopedSetSessionWriteTransaction;
+  friend class ScopedModelSafeGroupRestriction;
 
   // The context for this session, guaranteed to outlive |this|.
   SyncSessionContext* const context_;
@@ -126,6 +132,14 @@ class SyncSession {
   // Used to determine if an auth error notification should be sent out.
   bool auth_failure_occurred_;
 
+  // The set of active ModelSafeWorkers for the duration of this session.
+  const std::vector<ModelSafeWorker*> workers_;
+
+  // Used to fail read/write operations on this SyncSession that don't obey the
+  // currently active ModelSafeWorker contract.
+  bool group_restriction_in_effect_;
+  ModelSafeGroup group_restriction_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncSession);
 };
 
@@ -147,6 +161,26 @@ class ScopedSetSessionWriteTransaction {
   DISALLOW_COPY_AND_ASSIGN(ScopedSetSessionWriteTransaction);
 };
 
+// A utility to restrict access to only those parts of the given SyncSession
+// that pertain to the specified ModelSafeGroup.  See
+// SyncSession::ModelSafetyRestriction.
+class ScopedModelSafeGroupRestriction {
+ public:
+  ScopedModelSafeGroupRestriction(SyncSession* to_restrict,
+                               ModelSafeGroup restriction)
+      : session_(to_restrict) {
+    DCHECK(!session_->group_restriction_in_effect_);
+    session_->group_restriction_in_effect_ = true;
+    session_->group_restriction_ = restriction;
+  }
+  ~ScopedModelSafeGroupRestriction() {
+    session_->group_restriction_in_effect_ = true;
+  }
+ private:
+  SyncSession* session_;
+  DISALLOW_COPY_AND_ASSIGN(ScopedModelSafeGroupRestriction);
+};
+
 }  // namespace sessions
 }  // namespace browser_sync
 
diff --git a/chrome/browser/sync/sessions/sync_session_context.h b/chrome/browser/sync/sessions/sync_session_context.h
index 40deab1..3565ec6 100644
--- a/chrome/browser/sync/sessions/sync_session_context.h
+++ b/chrome/browser/sync/sessions/sync_session_context.h
@@ -31,6 +31,7 @@ class DirectoryManager;
 namespace browser_sync {
 
 class ConflictResolver;
+class ModelSafeWorkerRegistrar;
 class ServerConnectionManager;
 
 namespace sessions {
@@ -41,12 +42,12 @@ class SyncSessionContext {
  public:
   SyncSessionContext(ServerConnectionManager* connection_manager,
                      syncable::DirectoryManager* directory_manager,
-                     ModelSafeWorker* model_safe_worker)
+                     ModelSafeWorkerRegistrar* model_safe_worker_registrar)
       : resolver_(NULL),
         syncer_event_channel_(NULL),
         connection_manager_(connection_manager),
         directory_manager_(directory_manager),
-        model_safe_worker_(model_safe_worker),
+        registrar_(model_safe_worker_registrar),
         extensions_activity_monitor_(new ExtensionsActivityMonitor()),
         notifications_enabled_(false) {
   }
@@ -69,8 +70,8 @@ class SyncSessionContext {
   SyncerEventChannel* syncer_event_channel() {
     return syncer_event_channel_;
   }
-  ModelSafeWorker* model_safe_worker() {
-    return model_safe_worker_.get();
+  ModelSafeWorkerRegistrar* registrar() {
+    return registrar_;
   }
   ExtensionsActivityMonitor* extensions_monitor() {
     return extensions_activity_monitor_;
@@ -103,9 +104,9 @@ class SyncSessionContext {
   ServerConnectionManager* const connection_manager_;
   syncable::DirectoryManager* const directory_manager_;
 
-  // A worker capable of processing work closures on a thread that is
-  // guaranteed to be safe for model modifications.
-  scoped_ptr<ModelSafeWorker> model_safe_worker_;
+  // A registrar of workers capable of processing work closures on a thread
+  // that is guaranteed to be safe for model modifications.
+  ModelSafeWorkerRegistrar* registrar_;
 
   // We use this to stuff extensions activity into CommitMessages so the server
   // can correlate commit traffic with extension-related bookmark mutations.
diff --git a/chrome/browser/sync/sessions/sync_session_unittest.cc b/chrome/browser/sync/sessions/sync_session_unittest.cc
index e2a3c12..5ac602d 100644
--- a/chrome/browser/sync/sessions/sync_session_unittest.cc
+++ b/chrome/browser/sync/sessions/sync_session_unittest.cc
@@ -19,11 +19,12 @@ namespace sessions {
 namespace {
 
 class SyncSessionTest : public testing::Test,
-                        public SyncSession::Delegate {
+                        public SyncSession::Delegate,
+                        public ModelSafeWorkerRegistrar {
  public:
   SyncSessionTest() : controller_invocations_allowed_(false) {}
   virtual void SetUp() {
-    context_.reset(new SyncSessionContext(NULL, NULL, NULL));
+    context_.reset(new SyncSessionContext(NULL, NULL, this));
     session_.reset(new SyncSession(context_.get(), this));
   }
   virtual void TearDown() {
@@ -47,6 +48,10 @@ class SyncSessionTest : public testing::Test,
     FailControllerInvocationIfDisabled("OnReceivedShortPollIntervalUpdate");
   }
 
+  // ModelSafeWorkerRegistrar implementation.
+  virtual void GetWorkers(std::vector<ModelSafeWorker*>* out) {}
+  virtual void GetModelSafeRoutingInfo(ModelSafeRoutingInfo* out) {}
+
   StatusController* status() { return session_->status_controller(); }
  protected:
   void FailControllerInvocationIfDisabled(const std::string& msg) {
@@ -78,7 +83,7 @@ TEST_F(SyncSessionTest, SetWriteTransaction) {
   TestDirectorySetterUpper db;
   db.SetUp();
   session_.reset(NULL);
-  context_.reset(new SyncSessionContext(NULL, db.manager(), NULL));
+  context_.reset(new SyncSessionContext(NULL, db.manager(), this));
   session_.reset(new SyncSession(context_.get(), this));
   context_->set_account_name(db.name());
   syncable::ScopedDirLookup dir(context_->directory_manager(),