Revert 182527

Caused compile failure on Win Aura

> [Sync] Make SESSIONS an implicit type
> 
> We add TABS as a new local type, which is now what is enabled via the user
> settings. It implicitly enables SESSIONS.
> 
> Similarly, History now corresponds with Typed URLs, which implicitly enables 
> history delete directives if the proper command line flag is passed.
> 
> Finally, History delete directives implicitly enables SESSIONS, which we can do
> because Sessions is no longer a user selectable type.
> 
> BUG=170162
> TBR=jhawkins@chromium.org
> 
> Review URL: https://chromiumcodereview.appspot.com/11961030

TBR=zea@chromium.org
Review URL: https://codereview.chromium.org/12271002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182529 0039d316-1c4b-4281-b951-d872f2087c98

23 files changed, 44 insertions, 141 deletions

diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 01180b8..859b1be 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -6574,10 +6574,10 @@ Keep your key file in a safe place. You will need it to create new versions of y
       </if>
       <if expr="not pp_ifdef('android')">
         <message name="IDS_FLAGS_SYNC_TYPED_URLS_NAME" desc="Title for the flag to enable syncing the TypedUrl datatype">
-          Enable syncing History
+          Enable syncing Omnibox History
         </message>
         <message name="IDS_FLAGS_SYNC_TYPED_URLS_DESCRIPTION" desc="Description for the flag to enable syncing the TypedURL datatype">
-          Enable History in the sync settings. This allows syncing your typed URL history and navigation history to other clients to assist in omnibox auto-completion and the history UI.
+          Enable Omnibox History in the sync settings. This allows syncing your typed URL history to other clients to assist in omnibox auto-completion.
         </message>
       </if>
       <message name="IDS_FLAGS_OMNIBOX_HISTORY_QUICK_PROVIDER_NEW_SCORING_NAME" desc="Title for the flag for omnibox to use new scoring function in HistoryQuickProvider when ranking suggestions">
@@ -14032,8 +14032,8 @@ Some features may be unavailable.  Please check that the profile exists and you
       <message name="IDS_SYNC_DATATYPE_PASSWORDS" desc="Saved passwords, one of the data types that we allow syncing.">
         Passwords
       </message>
-      <message name="IDS_SYNC_DATATYPE_TYPED_URLS" desc="History, one of the data types that we allow syncing.">
-        History
+      <message name="IDS_SYNC_DATATYPE_TYPED_URLS" desc="Typed URLs, one of the data types that we allow syncing.">
+        Omnibox History
       </message>
       <message name="IDS_SYNC_DATATYPE_APPS" desc="Apps, one of the data types that we allow syncing.">
         Apps
diff --git a/chrome/browser/resources/sync_setup_overlay.html b/chrome/browser/resources/sync_setup_overlay.html
index 52ad806..0003d7f 100644
--- a/chrome/browser/resources/sync_setup_overlay.html
+++ b/chrome/browser/resources/sync_setup_overlay.html
@@ -235,9 +235,9 @@
                   </span>
                 </label>
               </div>
-              <div id="tabs-item" class="sync-type-checkbox checkbox">
+              <div id="sessions-item" class="sync-type-checkbox checkbox">
                 <label>
-                  <input id="tabs-checkbox" type="checkbox">
+                  <input id="sessions-checkbox" type="checkbox">
                   <span i18n-content="openTabs" il8n-values="title:tabs">
                   </span>
                 </label>
diff --git a/chrome/browser/resources/sync_setup_overlay.js b/chrome/browser/resources/sync_setup_overlay.js
index bf05b20..57957d0 100644
--- a/chrome/browser/resources/sync_setup_overlay.js
+++ b/chrome/browser/resources/sync_setup_overlay.js
@@ -269,7 +269,7 @@ cr.define('options', function() {
         'extensionsSynced': syncAll || $('extensions-checkbox').checked,
         'typedUrlsSynced': syncAll || $('typed-urls-checkbox').checked,
         'appsSynced': syncAll || $('apps-checkbox').checked,
-        'tabsSynced': syncAll || $('tabs-checkbox').checked,
+        'sessionsSynced': syncAll || $('sessions-checkbox').checked,
         'encryptAllData': encryptAllData,
         'usePassphrase': usePassphrase,
         'isGooglePassphrase': googlePassphrase,
@@ -370,11 +370,11 @@ cr.define('options', function() {
       } else {
         $('apps-item').hidden = true;
       }
-      if (args.tabsRegistered) {
-        $('tabs-checkbox').checked = args.tabsSynced;
-        $('tabs-item').hidden = false;
+      if (args.sessionsRegistered) {
+        $('sessions-checkbox').checked = args.sessionsSynced;
+        $('sessions-item').hidden = false;
       } else {
-        $('tabs-item').hidden = true;
+        $('sessions-item').hidden = true;
       }
 
       this.setCheckboxesToKeepEverythingSynced_(args.syncAllDataTypes);
diff --git a/chrome/browser/sync/glue/model_association_manager.cc b/chrome/browser/sync/glue/model_association_manager.cc
index 4dabe05..e748829 100644
--- a/chrome/browser/sync/glue/model_association_manager.cc
+++ b/chrome/browser/sync/glue/model_association_manager.cc
@@ -28,7 +28,6 @@ static const syncer::ModelType kStartOrder[] = {
   syncer::NIGORI,               //  Listed for completeness.
   syncer::DEVICE_INFO,          //  Listed for completeness.
   syncer::EXPERIMENTS,          //  Listed for completeness.
-  syncer::PROXY_TABS,           //  Listed for completeness.
   syncer::BOOKMARKS,            //  UI thread datatypes.
   syncer::PREFERENCES,
   syncer::PRIORITY_PREFERENCES,
diff --git a/chrome/browser/sync/profile_sync_components_factory_impl.cc b/chrome/browser/sync/profile_sync_components_factory_impl.cc
index 756f18d..0fe3a29 100644
--- a/chrome/browser/sync/profile_sync_components_factory_impl.cc
+++ b/chrome/browser/sync/profile_sync_components_factory_impl.cc
@@ -39,7 +39,6 @@
 #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/glue/proxy_data_type_controller.h"
 #include "chrome/browser/sync/glue/search_engine_data_type_controller.h"
 #include "chrome/browser/sync/glue/session_change_processor.h"
 #include "chrome/browser/sync/glue/session_data_type_controller.h"
@@ -72,7 +71,6 @@ using browser_sync::BookmarkChangeProcessor;
 using browser_sync::BookmarkDataTypeController;
 using browser_sync::BookmarkModelAssociator;
 using browser_sync::DataTypeController;
-using browser_sync::DataTypeErrorHandler;
 using browser_sync::DataTypeManager;
 using browser_sync::DataTypeManagerImpl;
 using browser_sync::DataTypeManagerObserver;
@@ -82,7 +80,6 @@ using browser_sync::GenericChangeProcessor;
 using browser_sync::PasswordChangeProcessor;
 using browser_sync::PasswordDataTypeController;
 using browser_sync::PasswordModelAssociator;
-using browser_sync::ProxyDataTypeController;
 using browser_sync::SearchEngineDataTypeController;
 using browser_sync::SessionChangeProcessor;
 using browser_sync::SessionDataTypeController;
@@ -94,6 +91,7 @@ using browser_sync::TypedUrlChangeProcessor;
 using browser_sync::TypedUrlDataTypeController;
 using browser_sync::TypedUrlModelAssociator;
 using browser_sync::UIDataTypeController;
+using browser_sync::DataTypeErrorHandler;
 using content::BrowserThread;
 
 ProfileSyncComponentsFactoryImpl::ProfileSyncComponentsFactoryImpl(
@@ -151,8 +149,6 @@ void ProfileSyncComponentsFactoryImpl::RegisterCommonDataTypes(
   // Session sync is enabled by default.  Register unless explicitly disabled.
   if (!command_line_->HasSwitch(switches::kDisableSyncTabs)) {
     pss->RegisterDataTypeController(
-        new ProxyDataTypeController(syncer::PROXY_TABS));
-    pss->RegisterDataTypeController(
         new SessionDataTypeController(this, profile_, pss));
   }
 
diff --git a/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc b/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc
index c704437..311299c 100644
--- a/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc
+++ b/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc
@@ -48,7 +48,6 @@ class ProfileSyncComponentsFactoryImplTest : public testing::Test {
     datatypes.push_back(syncer::PREFERENCES);
     datatypes.push_back(syncer::SEARCH_ENGINES);
     datatypes.push_back(syncer::SESSIONS);
-    datatypes.push_back(syncer::PROXY_TABS);
     datatypes.push_back(syncer::THEMES);
     datatypes.push_back(syncer::TYPED_URLS);
     return datatypes;
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 2e454e5..b649c14 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -1333,7 +1333,7 @@ void ProfileSyncService::UpdateSelectedTypesHistogram(
     syncer::EXTENSIONS,
     syncer::PASSWORDS,
     syncer::PREFERENCES,
-    syncer::PROXY_TABS,
+    syncer::SESSIONS,
     syncer::SYNCED_NOTIFICATIONS,
     syncer::THEMES,
     syncer::TYPED_URLS
@@ -1347,13 +1347,13 @@ void ProfileSyncService::UpdateSelectedTypesHistogram(
     browser_sync::user_selectable_type::EXTENSIONS,
     browser_sync::user_selectable_type::PASSWORDS,
     browser_sync::user_selectable_type::PREFERENCES,
-    browser_sync::user_selectable_type::PROXY_TABS,
+    browser_sync::user_selectable_type::SESSIONS,
     browser_sync::user_selectable_type::SYNCED_NOTIFICATIONS,
     browser_sync::user_selectable_type::THEMES,
     browser_sync::user_selectable_type::TYPED_URLS
   };
 
-  COMPILE_ASSERT(24 == syncer::MODEL_TYPE_COUNT, UpdateCustomConfigHistogram);
+  COMPILE_ASSERT(23 == syncer::MODEL_TYPE_COUNT, UpdateCustomConfigHistogram);
   COMPILE_ASSERT(arraysize(model_types) ==
                  browser_sync::user_selectable_type::SELECTABLE_DATATYPE_COUNT,
                  UpdateCustomConfigHistogram);
@@ -1393,8 +1393,7 @@ void ProfileSyncService::RefreshSpareBootstrapToken(
 }
 #endif
 
-void ProfileSyncService::OnUserChoseDatatypes(
-    bool sync_everything,
+void ProfileSyncService::OnUserChoseDatatypes(bool sync_everything,
     syncer::ModelTypeSet chosen_types) {
   if (!backend_.get() && !HasUnrecoverableError()) {
     NOTREACHED();
diff --git a/chrome/browser/sync/profile_sync_service_harness.cc b/chrome/browser/sync/profile_sync_service_harness.cc
index eb4a4c4..7b5d337 100644
--- a/chrome/browser/sync/profile_sync_service_harness.cc
+++ b/chrome/browser/sync/profile_sync_service_harness.cc
@@ -32,8 +32,6 @@
 
 using syncer::sessions::SyncSessionSnapshot;
 
-namespace {
-
 // TODO(rsimha): Remove the following lines once crbug.com/91863 is fixed.
 // The amount of time for which we wait for a live sync operation to complete.
 static const int kLiveSyncOperationTimeoutMs = 45000;
@@ -41,20 +39,6 @@ static const int kLiveSyncOperationTimeoutMs = 45000;
 // The amount of time we wait for test cases that verify exponential backoff.
 static const int kExponentialBackoffVerificationTimeoutMs = 60000;
 
-syncer::ModelTypeSet GetUserVisibleTypes() {
-  syncer::ModelTypeSet user_visible_types(syncer::UserTypes());
-  user_visible_types.Remove(syncer::APP_NOTIFICATIONS);
-  user_visible_types.Remove(syncer::APP_SETTINGS);
-  user_visible_types.Remove(syncer::AUTOFILL_PROFILE);
-  user_visible_types.Remove(syncer::EXTENSION_SETTINGS);
-  user_visible_types.Remove(syncer::SEARCH_ENGINES);
-  user_visible_types.Remove(syncer::SESSIONS);
-  user_visible_types.Remove(syncer::HISTORY_DELETE_DIRECTIVES);
-  return user_visible_types;
-}
-
-}
-
 // Simple class to implement a timeout using PostDelayedTask.  If it is not
 // aborted before picked up by a message queue, then it asserts with the message
 // provided.  This class is not thread safe.
@@ -964,7 +948,6 @@ bool ProfileSyncServiceHarness::DisableSyncForDatatype(
     return true;
   }
 
-  synced_datatypes.RetainAll(GetUserVisibleTypes());
   synced_datatypes.Remove(datatype);
   service()->OnUserChoseDatatypes(false, synced_datatypes);
   if (AwaitFullSyncCompletion("Datatype reconfiguration.")) {
diff --git a/chrome/browser/sync/sync_prefs.cc b/chrome/browser/sync/sync_prefs.cc
index d4b488c..9c53203 100644
--- a/chrome/browser/sync/sync_prefs.cc
+++ b/chrome/browser/sync/sync_prefs.cc
@@ -4,7 +4,6 @@
 
 #include "chrome/browser/sync/sync_prefs.h"
 
-#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/public/pref_member.h"
@@ -15,7 +14,6 @@
 #include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/common/chrome_notification_types.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
@@ -326,8 +324,6 @@ const char* SyncPrefs::GetPrefNameForDataType(syncer::ModelType data_type) {
       return prefs::kSyncSyncedNotifications;
     case syncer::DICTIONARY:
       return prefs::kSyncDictionary;
-    case syncer::PROXY_TABS:
-      return prefs::kSyncTabs;
     default:
       break;
   }
@@ -395,12 +391,8 @@ void SyncPrefs::RegisterPrefGroups() {
   pref_groups_[syncer::PREFERENCES].Put(syncer::DICTIONARY);
   pref_groups_[syncer::PREFERENCES].Put(syncer::SEARCH_ENGINES);
 
-  pref_groups_[syncer::TYPED_URLS].Put(syncer::HISTORY_DELETE_DIRECTIVES);
-
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  if (command_line.HasSwitch(switches::kHistoryEnableFullHistorySync))
-    pref_groups_[syncer::TYPED_URLS].Put(syncer::SESSIONS);
-  pref_groups_[syncer::PROXY_TABS].Put(syncer::SESSIONS);
+  // TODO(akalin): Revisit this once UI lands.
+  pref_groups_[syncer::SESSIONS].Put(syncer::HISTORY_DELETE_DIRECTIVES);
 }
 
 // static
@@ -426,13 +418,6 @@ bool SyncPrefs::GetDataTypePreferred(syncer::ModelType type) const {
     NOTREACHED();
     return false;
   }
-  if (type == syncer::PROXY_TABS &&
-      pref_service_->GetUserPrefValue(pref_name) == NULL &&
-      pref_service_->IsUserModifiablePreference(pref_name)) {
-    // If there is no tab sync preference yet (i.e. newly enabled type),
-    // default to the session sync preference value.
-    pref_name = GetPrefNameForDataType(syncer::SESSIONS);
-  }
 
   return pref_service_->GetBoolean(pref_name);
 }
@@ -458,6 +443,8 @@ syncer::ModelTypeSet SyncPrefs::ResolvePrefGroups(
       i != pref_groups_.end(); ++i) {
     if (types.Has(i->first))
       types_with_groups.PutAll(i->second);
+    else
+      types_with_groups.RemoveAll(i->second);
   }
   types_with_groups.RetainAll(registered_types);
   return types_with_groups;
diff --git a/chrome/browser/sync/sync_prefs_unittest.cc b/chrome/browser/sync/sync_prefs_unittest.cc
index 9311ec8..d963bab 100644
--- a/chrome/browser/sync/sync_prefs_unittest.cc
+++ b/chrome/browser/sync/sync_prefs_unittest.cc
@@ -4,10 +4,8 @@
 
 #include "chrome/browser/sync/sync_prefs.h"
 
-#include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/time.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/testing_pref_service_syncable.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -23,8 +21,6 @@ using ::testing::StrictMock;
 class SyncPrefsTest : public testing::Test {
  protected:
   virtual void SetUp() OVERRIDE {
-    CommandLine::ForCurrentProcess()->AppendSwitch(
-        switches::kHistoryEnableFullHistorySync);
     SyncPrefs::RegisterUserPrefs(&pref_service_,
                                  pref_service_.registry());
   }
@@ -44,8 +40,6 @@ syncer::ModelTypeSet GetUserVisibleTypes() {
   user_visible_types.Remove(syncer::DICTIONARY);
   user_visible_types.Remove(syncer::EXTENSION_SETTINGS);
   user_visible_types.Remove(syncer::SEARCH_ENGINES);
-  user_visible_types.Remove(syncer::SESSIONS);
-  user_visible_types.Remove(syncer::HISTORY_DELETE_DIRECTIVES);
   return user_visible_types;
 }
 
@@ -125,12 +119,13 @@ TEST_F(SyncPrefsTest, PreferredTypesNotKeepEverythingSynced) {
     if (it.Get() == syncer::EXTENSIONS) {
       expected_preferred_types.Put(syncer::EXTENSION_SETTINGS);
     }
-    if (it.Get() == syncer::TYPED_URLS) {
+    if (it.Get() == syncer::SESSIONS) {
       expected_preferred_types.Put(syncer::HISTORY_DELETE_DIRECTIVES);
-      expected_preferred_types.Put(syncer::SESSIONS);
     }
-    if (it.Get() == syncer::PROXY_TABS) {
-      expected_preferred_types.Put(syncer::SESSIONS);
+    // TODO(akalin): Remove this when history delete directives are
+    // registered by default.
+    if (it.Get() == syncer::HISTORY_DELETE_DIRECTIVES) {
+      expected_preferred_types.Clear();
     }
     sync_prefs.SetPreferredDataTypes(user_types, preferred_types);
     EXPECT_TRUE(expected_preferred_types.Equals(
diff --git a/chrome/browser/sync/test/integration/enable_disable_test.cc b/chrome/browser/sync/test/integration/enable_disable_test.cc
index 38ba937..0915056 100644
--- a/chrome/browser/sync/test/integration/enable_disable_test.cc
+++ b/chrome/browser/sync/test/integration/enable_disable_test.cc
@@ -57,25 +57,17 @@ IN_PROC_BROWSER_TEST_F(EnableDisableSingleClientTest, EnableOneAtATime) {
     ASSERT_TRUE(GetClient(0)->EnableSyncForDatatype(it.Get()));
 
     // AUTOFILL_PROFILE is lumped together with AUTOFILL.
-    // SESSIONS is lumped together with PROXY_TABS and
-    // HISTORY_DELETE_DIRECTIVES.
-    if (it.Get() == syncer::AUTOFILL_PROFILE || it.Get() == syncer::SESSIONS) {
+    if (it.Get() == syncer::AUTOFILL_PROFILE) {
       continue;
     }
 
-    if (!syncer::ProxyTypes().Has(it.Get())) {
-      ASSERT_TRUE(DoesTopLevelNodeExist(user_share, it.Get()))
-          << syncer::ModelTypeToString(it.Get());
-    }
+    ASSERT_TRUE(DoesTopLevelNodeExist(user_share, it.Get()))
+        << syncer::ModelTypeToString(it.Get());
 
     // AUTOFILL_PROFILE is lumped together with AUTOFILL.
     if (it.Get() == syncer::AUTOFILL) {
       ASSERT_TRUE(DoesTopLevelNodeExist(user_share,
                                         syncer::AUTOFILL_PROFILE));
-    } else if (it.Get() == syncer::HISTORY_DELETE_DIRECTIVES ||
-               it.Get() == syncer::PROXY_TABS) {
-      ASSERT_TRUE(DoesTopLevelNodeExist(user_share,
-                                        syncer::SESSIONS));
     }
   }
 
@@ -101,9 +93,7 @@ IN_PROC_BROWSER_TEST_F(EnableDisableSingleClientTest, DisableOneAtATime) {
   // Make sure all top-level nodes exist first.
   for (syncer::ModelTypeSet::Iterator it = registered_types.First();
        it.Good(); it.Inc()) {
-    if (!syncer::ProxyTypes().Has(it.Get())) {
-      ASSERT_TRUE(DoesTopLevelNodeExist(user_share, it.Get()));
-    }
+    ASSERT_TRUE(DoesTopLevelNodeExist(user_share, it.Get()));
   }
 
   for (syncer::ModelTypeSet::Iterator it = registered_types.First();
@@ -111,9 +101,7 @@ IN_PROC_BROWSER_TEST_F(EnableDisableSingleClientTest, DisableOneAtATime) {
     ASSERT_TRUE(GetClient(0)->DisableSyncForDatatype(it.Get()));
 
     // AUTOFILL_PROFILE is lumped together with AUTOFILL.
-    // SESSIONS is lumped together with PROXY_TABS and
-    // HISTORY_DELETE_DIRECTIVES.
-    if (it.Get() == syncer::AUTOFILL_PROFILE || it.Get() == syncer::SESSIONS) {
+    if (it.Get() == syncer::AUTOFILL_PROFILE) {
       continue;
     }
 
@@ -127,10 +115,6 @@ IN_PROC_BROWSER_TEST_F(EnableDisableSingleClientTest, DisableOneAtATime) {
     if (it.Get() == syncer::AUTOFILL) {
       ASSERT_FALSE(DoesTopLevelNodeExist(user_share,
                                          syncer::AUTOFILL_PROFILE));
-    } else if (it.Get() == syncer::HISTORY_DELETE_DIRECTIVES ||
-               it.Get() == syncer::PROXY_TABS) {
-      ASSERT_FALSE(DoesTopLevelNodeExist(user_share,
-                                         syncer::SESSIONS));
     }
   }
 
diff --git a/chrome/browser/sync/user_selectable_sync_type.h b/chrome/browser/sync/user_selectable_sync_type.h
index 56440a6..143aa77 100644
--- a/chrome/browser/sync/user_selectable_sync_type.h
+++ b/chrome/browser/sync/user_selectable_sync_type.h
@@ -29,7 +29,7 @@ enum UserSelectableSyncType {
   THEMES = 4,
   TYPED_URLS = 5,
   EXTENSIONS = 6,
-  PROXY_TABS = 7,
+  SESSIONS = 7,
   APPS = 8,
   SYNCED_NOTIFICATIONS = 9,
 
@@ -46,8 +46,6 @@ enum UserSelectableSyncType {
   // DEVICE_INFO,
   // EXPERIMENTS,
   // PRIORITY_PREFERENCES,
-  // SESSIONS,
-  // HISTORY_DELETE_DIRECTIVES,
 
   // Number of sync datatypes exposed to the user via checboxes in the UI.
   SELECTABLE_DATATYPE_COUNT = 10,
diff --git a/chrome/browser/ui/webui/ntp/foreign_session_handler.cc b/chrome/browser/ui/webui/ntp/foreign_session_handler.cc
index 0515759..d924246 100644
--- a/chrome/browser/ui/webui/ntp/foreign_session_handler.cc
+++ b/chrome/browser/ui/webui/ntp/foreign_session_handler.cc
@@ -222,7 +222,7 @@ bool ForeignSessionHandler::IsTabSyncEnabled() {
   Profile* profile = Profile::FromWebUI(web_ui());
   ProfileSyncService* service =
       ProfileSyncServiceFactory::GetInstance()->GetForProfile(profile);
-  return service && service->GetPreferredDataTypes().Has(syncer::PROXY_TABS);
+  return service && service->GetPreferredDataTypes().Has(syncer::SESSIONS);
 }
 
 string16 ForeignSessionHandler::FormatSessionTime(const base::Time& time) {
diff --git a/chrome/browser/ui/webui/sync_setup_handler.cc b/chrome/browser/ui/webui/sync_setup_handler.cc
index 3ef6f06..8e2bf6d 100644
--- a/chrome/browser/ui/webui/sync_setup_handler.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler.cc
@@ -78,7 +78,7 @@ const char* kDataTypeNames[] = {
   "extensions",
   "passwords",
   "preferences",
-  "tabs",
+  "sessions",
   "themes",
   "typedUrls"
 };
@@ -90,7 +90,7 @@ const syncer::ModelType kDataTypes[] = {
   syncer::EXTENSIONS,
   syncer::PASSWORDS,
   syncer::PREFERENCES,
-  syncer::PROXY_TABS,
+  syncer::SESSIONS,
   syncer::THEMES,
   syncer::TYPED_URLS
 };
diff --git a/chrome/browser/ui/webui/sync_setup_handler_unittest.cc b/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
index e152822..abea6a3 100644
--- a/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
@@ -56,7 +56,7 @@ const syncer::ModelType kUserSelectableTypes[] = {
   syncer::EXTENSIONS,
   syncer::PASSWORDS,
   syncer::PREFERENCES,
-  syncer::PROXY_TABS,
+  syncer::SESSIONS,
   syncer::THEMES,
   syncer::TYPED_URLS
 };
@@ -102,7 +102,7 @@ std::string GetConfiguration(const DictionaryValue* extra_values,
   result.SetBoolean("extensionsSynced", types.Has(syncer::EXTENSIONS));
   result.SetBoolean("passwordsSynced", types.Has(syncer::PASSWORDS));
   result.SetBoolean("preferencesSynced", types.Has(syncer::PREFERENCES));
-  result.SetBoolean("tabsSynced", types.Has(syncer::PROXY_TABS));
+  result.SetBoolean("sessionsSynced", types.Has(syncer::SESSIONS));
   result.SetBoolean("themesSynced", types.Has(syncer::THEMES));
   result.SetBoolean("typedUrlsSynced", types.Has(syncer::TYPED_URLS));
   std::string args;
@@ -201,7 +201,7 @@ void CheckConfigDataTypeArguments(DictionaryValue* dictionary,
   CheckBool(dictionary, "extensionsSynced", types.Has(syncer::EXTENSIONS));
   CheckBool(dictionary, "passwordsSynced", types.Has(syncer::PASSWORDS));
   CheckBool(dictionary, "preferencesSynced", types.Has(syncer::PREFERENCES));
-  CheckBool(dictionary, "tabsSynced", types.Has(syncer::PROXY_TABS));
+  CheckBool(dictionary, "sessionsSynced", types.Has(syncer::SESSIONS));
   CheckBool(dictionary, "themesSynced", types.Has(syncer::THEMES));
   CheckBool(dictionary, "typedUrlsSynced", types.Has(syncer::TYPED_URLS));
 }
@@ -1120,7 +1120,7 @@ TEST_P(SyncSetupHandlerTest, ShowSetupSyncEverything) {
   CheckBool(dictionary, "extensionsRegistered", true);
   CheckBool(dictionary, "passwordsRegistered", true);
   CheckBool(dictionary, "preferencesRegistered", true);
-  CheckBool(dictionary, "tabsRegistered", true);
+  CheckBool(dictionary, "sessionsRegistered", true);
   CheckBool(dictionary, "themesRegistered", true);
   CheckBool(dictionary, "typedUrlsRegistered", true);
   CheckBool(dictionary, "showPassphrase", false);
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index d881ec2..12a9a13 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1739,7 +1739,6 @@ const char kSyncSessions[] = "sync.sessions";
 const char kSyncHistoryDeleteDirectives[] = "sync.history_delete_directives";
 const char kSyncSyncedNotifications[] = "sync.synced_notifications";
 const char kSyncDictionary[] = "sync.dictionary";
-const char kSyncTabs[] = "sync.tabs";
 
 // Boolean used by enterprise configuration management in order to lock down
 // sync.
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
index e269b9c..8f26c1b 100644
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -618,7 +618,6 @@ extern const char kSyncSearchEngines[];
 extern const char kSyncSessions[];
 extern const char kSyncSuppressStart[];
 extern const char kSyncSyncedNotifications[];
-extern const char kSyncTabs[];
 extern const char kGoogleServicesLastUsername[];
 extern const char kGoogleServicesUsername[];
 extern const char kGoogleServicesUsernamePattern[];
diff --git a/sync/internal_api/public/base/model_type.h b/sync/internal_api/public/base/model_type.h
index 882c821..8eaf5d0 100644
--- a/sync/internal_api/public/base/model_type.h
+++ b/sync/internal_api/public/base/model_type.h
@@ -49,11 +49,6 @@ enum ModelType {
   // can be represented in the protocol using a specific Message type in the
   // EntitySpecifics protocol buffer.
   //
-  // WARNING: Modifying the order of these types or inserting a new type above
-  // these will affect numerous histograms that rely on the enum values being
-  // consistent. When adding a new type, add it to the end of the user model
-  // types section, but before the proxy types.
-  //
   // A bookmark folder or a bookmark URL object.
   BOOKMARKS,
   FIRST_USER_MODEL_TYPE = BOOKMARKS,  // Declared 2nd, for debugger prettiness.
@@ -67,6 +62,7 @@ enum ModelType {
   AUTOFILL_PROFILE,
   // An autofill folder or an autofill object.
   AUTOFILL,
+
   // A themes folder or a themes object.
   THEMES,
   // A typed_url folder or a typed_url object.
@@ -91,22 +87,8 @@ enum ModelType {
   SYNCED_NOTIFICATIONS,
   // Custom spelling dictionary.
   DICTIONARY,
+  LAST_USER_MODEL_TYPE = DICTIONARY,
 
-  // ---- Proxy types ----
-  // Proxy types are excluded from the sync protocol, but are still considered
-  // real user types. By convention, we prefix them with 'PROXY_' to distinguish
-  // them from normal protocol types.
-
-  // Tab sync. This is a placeholder type, so that Sessions can be implicitly
-  // enabled for history sync and tabs sync.
-  PROXY_TABS,
-
-  FIRST_PROXY_TYPE = PROXY_TABS,
-  LAST_PROXY_TYPE = PROXY_TABS,
-
-  LAST_USER_MODEL_TYPE = PROXY_TABS,
-
-  // ---- Control Types ----
   // An object representing a set of Nigori keys.
   NIGORI,
   FIRST_CONTROL_MODEL_TYPE = NIGORI,
diff --git a/sync/protocol/proto_value_conversions.cc b/sync/protocol/proto_value_conversions.cc
index ee5580e..886d55a 100644
--- a/sync/protocol/proto_value_conversions.cc
+++ b/sync/protocol/proto_value_conversions.cc
@@ -581,7 +581,6 @@ DictionaryValue* GetUpdatesMessageToValue(
   SET_INT32(batch_size);
   SET_REP(from_progress_marker, DataTypeProgressMarkerToValue);
   SET_BOOL(streaming);
-  SET_BOOL(need_encryption_key);
   SET_BOOL(create_mobile_bookmarks_folder);
   return value;
 }
@@ -739,7 +738,6 @@ base::DictionaryValue* ClientConfigParamsToValue(
     const sync_pb::ClientConfigParams& proto) {
   DictionaryValue* value = new DictionaryValue();
   SET_INT32_REP(enabled_type_ids);
-  SET_BOOL(tabs_datatype_enabled);
   return value;
 }
 
diff --git a/sync/protocol/proto_value_conversions_unittest.cc b/sync/protocol/proto_value_conversions_unittest.cc
index 8ed5440..74ae4f2 100644
--- a/sync/protocol/proto_value_conversions_unittest.cc
+++ b/sync/protocol/proto_value_conversions_unittest.cc
@@ -50,7 +50,7 @@ TEST_F(ProtoValueConversionsTest, ProtoChangeCheck) {
   // If this number changes, that means we added or removed a data
   // type.  Don't forget to add a unit test for {New
   // type}SpecificsToValue below.
-  EXPECT_EQ(24, MODEL_TYPE_COUNT);
+  EXPECT_EQ(23, MODEL_TYPE_COUNT);
 
   // We'd also like to check if we changed any field in our messages.
   // However, that's hard to do: sizeof could work, but it's
@@ -232,8 +232,7 @@ TEST_F(ProtoValueConversionsTest, EntitySpecificsToValue) {
 #undef SET_FIELD
 
   scoped_ptr<DictionaryValue> value(EntitySpecificsToValue(specifics));
-  EXPECT_EQ(MODEL_TYPE_COUNT - FIRST_REAL_MODEL_TYPE -
-            (LAST_PROXY_TYPE - FIRST_PROXY_TYPE + 1),
+  EXPECT_EQ(MODEL_TYPE_COUNT - FIRST_REAL_MODEL_TYPE,
             static_cast<int>(value->size()));
 }
 
diff --git a/sync/protocol/sync.proto b/sync/protocol/sync.proto
index a74089e..44dd5908 100644
--- a/sync/protocol/sync.proto
+++ b/sync/protocol/sync.proto
@@ -366,13 +366,8 @@ message ChromiumExtensionsActivity {
 
 // Client specific configuration information.
 message ClientConfigParams {
-  // The set of data types this client has enabled. Note that this does not
-  // include proxy types, as they do not have protocol field numbers and are
-  // placeholder types that implicitly enable protocol types.
+  // The set of data types this client has enabled.
  repeated int32 enabled_type_ids = 1;
-
- // Whether the PROXY_TABS proxy datatype is enabled on this client.
- optional bool tabs_datatype_enabled = 2;
 };
 
 message CommitMessage {
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index 2bdb7cb..0847810 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -341,7 +341,7 @@ ModelTypeSet ControlTypes() {
 
 ModelTypeSet ProxyTypes() {
   ModelTypeSet set;
-  set.Put(PROXY_TABS);
+  // TODO(zea): add a TABS type here.
   return set;
 }
 
@@ -400,8 +400,6 @@ const char* ModelTypeToString(ModelType model_type) {
       return "Priority Preferences";
     case DICTIONARY:
       return "Dictionary";
-    case PROXY_TABS:
-      return "Tabs";
     default:
       break;
   }
@@ -479,8 +477,6 @@ ModelType ModelTypeFromString(const std::string& model_type_string) {
     return PRIORITY_PREFERENCES;
   else if (model_type_string == "Dictionary")
     return DICTIONARY;
-  else if (model_type_string == "Tabs")
-    return PROXY_TABS;
   else
     NOTREACHED() << "No known model type corresponding to "
                  << model_type_string << ".";
@@ -563,8 +559,6 @@ std::string ModelTypeToRootTag(ModelType type) {
       return "google_chrome_priority_preferences";
     case DICTIONARY:
       return "google_chrome_dictionary";
-    case PROXY_TABS:
-      return std::string();
     default:
       break;
   }
diff --git a/sync/util/data_type_histogram.h b/sync/util/data_type_histogram.h
index 75e833e..e72cebb 100644
--- a/sync/util/data_type_histogram.h
+++ b/sync/util/data_type_histogram.h
@@ -99,9 +99,6 @@
       case ::syncer::DICTIONARY: \
         PER_DATA_TYPE_MACRO("Dictionary"); \
         break; \
-      case ::syncer::PROXY_TABS :\
-        PER_DATA_TYPE_MACRO("Tabs"); \
-        break; \
       default: \
         NOTREACHED() << "Unknown datatype " \
                      << ::syncer::ModelTypeToString(datatype);  \