move V2 classes in chrome/engine to syncer_v2 namespace

sync/engine/model_type_sync_proxy.h

Index: sync/engine/model_type_sync_proxy.h
diff --git a/sync/engine/model_type_sync_proxy.h b/sync/engine/model_type_sync_proxy.h
index 1568a3cfe8875b5aafafe7d12622c5137accd0c3..5385542572d81ca31f9610cd6067d926981e1a5d 100644
--- a/sync/engine/model_type_sync_proxy.h
+++ b/sync/engine/model_type_sync_proxy.h
@@ -8,7 +8,7 @@
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/non_blocking_sync_common.h"
 
-namespace syncer {
+namespace syncer_v2 {
 
 // Interface used by sync backend to issue requests to a synced data type.
 class SYNC_EXPORT_PRIVATE ModelTypeSyncProxy {
@@ -17,12 +17,12 @@ class SYNC_EXPORT_PRIVATE ModelTypeSyncProxy {
   virtual ~ModelTypeSyncProxy();
 
   virtual void OnCommitCompleted(
-      const syncer_v2::DataTypeState& type_state,
-      const syncer_v2::CommitResponseDataList& response_list) = 0;
+      const DataTypeState& type_state,
+      const CommitResponseDataList& response_list) = 0;
   virtual void OnUpdateReceived(
-      const syncer_v2::DataTypeState& type_state,
-      const syncer_v2::UpdateResponseDataList& response_list,
-      const syncer_v2::UpdateResponseDataList& pending_updates) = 0;
+      const DataTypeState& type_state,
+      const UpdateResponseDataList& response_list,
+      const UpdateResponseDataList& pending_updates) = 0;
 };
 
 }  // namespace syncer