[Sync] Add plumbing of context from client to server

sync/engine/non_blocking_type_processor_core.h

Index: sync/engine/non_blocking_type_processor_core.h
diff --git a/sync/engine/non_blocking_type_processor_core.h b/sync/engine/non_blocking_type_processor_core.h
index 412d2ddcabd505245b3d729af286967a4438d84f..a1ec817392e46c2bd94ea5e4b44f3c60960260fb 100644
--- a/sync/engine/non_blocking_type_processor_core.h
+++ b/sync/engine/non_blocking_type_processor_core.h
@@ -57,10 +57,14 @@ class SYNC_EXPORT NonBlockingTypeProcessorCore
   // UpdateHandler implementation.
   virtual void GetDownloadProgress(
       sync_pb::DataTypeProgressMarker* progress_marker) const OVERRIDE;
+  virtual void GetDataTypeContext(
+      sync_pb::DataTypeContext* context) const OVERRIDE;
   virtual void ProcessGetUpdatesResponse(
       const sync_pb::DataTypeProgressMarker& progress_marker,
       const SyncEntityList& applicable_updates,
       sessions::StatusController* status) OVERRIDE;
+  virtual void ProcessDataTypeContextMutation(
+      const sync_pb::DataTypeContext& mutated_context) OVERRIDE;
   virtual void ApplyUpdates(sessions::StatusController* status) OVERRIDE;
   virtual void PassiveApplyUpdates(sessions::StatusController* status) OVERRIDE;