sync: Add ControlPreference protobuf and supporting code

sync/internal_api/public/write_node.h

 // Copyright 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 SYNC_INTERNAL_API_PUBLIC_WRITE_NODE_H_
 #define SYNC_INTERNAL_API_PUBLIC_WRITE_NODE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 148 matching lines @@
   void SetSessionSpecifics(const sync_pb::SessionSpecifics& specifics);
 
   // Set the device info specifics.
   // Should only be called if GetModelType() == DEVICE_INFO.
   void SetDeviceInfoSpecifics(const sync_pb::DeviceInfoSpecifics& specifics);
 
   // Set the experiments specifics.
   // Should only be called if GetModelType() == EXPERIMENTS.
   void SetExperimentsSpecifics(const sync_pb::ExperimentsSpecifics& specifics);
 
+  // Set the priority preference specifics.
+  // Should only be called if GetModelType() == PRIORITY_PREFERENCE.
+  void SetPriorityPreferenceSpecifics(
+      const sync_pb::PriorityPreferenceSpecifics& specifics);
+
   // Implementation of BaseNode's abstract virtual accessors.
   virtual const syncable::Entry* GetEntry() const OVERRIDE;
 
   virtual const BaseTransaction* GetTransaction() const OVERRIDE;
 
   syncable::MutableEntry* GetMutableEntryForTest();
 
  private:
   FRIEND_TEST_ALL_PREFIXES(SyncManagerTest, EncryptBookmarksWithLegacyData);
 
@@ skipping 14 matching lines @@
 
   // The sync API transaction that is the parent of this node.
   WriteTransaction* transaction_;
 
   DISALLOW_COPY_AND_ASSIGN(WriteNode);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_WRITE_NODE_H_