sync: Add GetAllSyncData to sync/api

sync/api/syncable_service.h

Index: sync/api/syncable_service.h
diff --git a/sync/api/syncable_service.h b/sync/api/syncable_service.h
index 13225ca98463c6f9c728d2b5b77b3d44c35bd73e..81b6018b32afb23a18d939fd8078a528dcf76def 100644
--- a/sync/api/syncable_service.h
+++ b/sync/api/syncable_service.h
@@ -56,11 +56,6 @@ class SYNC_EXPORT SyncableService
   // Stop syncing the specified type and reset state.
   virtual void StopSyncing(ModelType type) = 0;
 
-  // Fills a list of SyncData from the local data. This should create an up
-  // to date representation of the SyncableService's view of that datatype, and
-  // should match/be a subset of the server's view of that datatype.
-  virtual SyncDataList GetAllSyncData(ModelType type) const = 0;
-
   // SyncChangeProcessor interface.
   // Process a list of new SyncChanges and update the local data as necessary.
   // Returns: A default SyncError (IsSet() == false) if no errors were