[Sync] Add support for dynamically enabling/disabling types

chrome/browser/sync/profile_sync_service.h

 // Copyright (c) 2012 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_PROFILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 527 matching lines @@
 
   // Returns whether sync is managed, i.e. controlled by configuration
   // management. If so, the user is not allowed to configure sync.
   virtual bool IsManaged() const;
 
   // syncer::UnrecoverableErrorHandler implementation.
   virtual void OnUnrecoverableError(
       const tracked_objects::Location& from_here,
       const std::string& message) OVERRIDE;
 
-  // Called when a datatype wishes to disable itself due to having hit an
-  // unrecoverable error.
-  virtual void DisableBrokenDatatype(
-      syncer::ModelType type,
-      const tracked_objects::Location& from_here,
-      std::string message);
+  // Called when a datatype wishes to disable itself. Note, this does not change
+  // preferred state of a datatype and is not persisted across restarts.
+  virtual void DisableDatatype(syncer::ModelType type,
+                               const tracked_objects::Location& from_here,
+                               std::string message);
+
+  // Called to re-enable a type disabled by DisableDatatype(..). Note, this does
+  // not change the preferred state of a datatype, and is not persisted across
+  // restarts.
+  void ReenableDatatype(syncer::ModelType type);
 
   // The functions below (until ActivateDataType()) should only be
   // called if sync_initialized() is true.
 
   // TODO(akalin): This is called mostly by ModelAssociators and
   // tests.  Figure out how to pass the handle to the ModelAssociators
   // directly, figure out how to expose this to tests, and remove this
   // function.
   virtual syncer::UserShare* GetUserShare() const;
 
@@ skipping 547 matching lines @@
   base::Callback<void(Profile*, base::Time, base::Time)> clear_browsing_data_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncService);
 };
 
 bool ShouldShowActionOnUI(
     const syncer::SyncProtocolError& error);
 
 
 #endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_