sync: Add ControlPreference protobuf and supporting code

sync/internal_api/base_node.cc

 // 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.
 
 #include "sync/internal_api/public/base_node.h"
 
 #include <stack>
 
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
@@ skipping 325 matching lines @@
 const sync_pb::DeviceInfoSpecifics& BaseNode::GetDeviceInfoSpecifics() const {
   DCHECK_EQ(GetModelType(), DEVICE_INFO);
   return GetEntitySpecifics().device_info();
 }
 
 const sync_pb::ExperimentsSpecifics& BaseNode::GetExperimentsSpecifics() const {
   DCHECK_EQ(GetModelType(), EXPERIMENTS);
   return GetEntitySpecifics().experiments();
 }
 
+const sync_pb::PriorityPreferenceSpecifics&
+    BaseNode::GetPriorityPreferenceSpecifics() const {
+  DCHECK_EQ(GetModelType(), PRIORITY_PREFERENCES);
+  return GetEntitySpecifics().priority_preference();
+}
+
 const sync_pb::EntitySpecifics& BaseNode::GetEntitySpecifics() const {
   return GetUnencryptedSpecifics(GetEntry());
 }
 
 ModelType BaseNode::GetModelType() const {
   return GetEntry()->GetModelType();
 }
 
 void BaseNode::SetUnencryptedSpecifics(
     const sync_pb::EntitySpecifics& specifics) {
   ModelType type = GetModelTypeFromSpecifics(specifics);
   DCHECK_NE(UNSPECIFIED, type);
   if (GetModelType() != UNSPECIFIED) {
     DCHECK_EQ(GetModelType(), type);
   }
   unencrypted_data_.CopyFrom(specifics);
 }
 
 }  // namespace syncer