Split up extensions storage API implementations for sync and local storage.

chrome/browser/extensions/api/storage/settings_sync_util.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 "chrome/browser/extensions/api/storage/settings_sync_util.h"
 
 #include "base/json/json_writer.h"
 #include "base/values.h"
+#include "chrome/browser/extensions/api/storage/settings_frontend.h"
+#include "chrome/browser/extensions/api/storage/sync_value_store_cache.h"
 #include "sync/protocol/app_setting_specifics.pb.h"
 #include "sync/protocol/extension_setting_specifics.pb.h"
 #include "sync/protocol/sync.pb.h"
 
 namespace extensions {
 
 namespace settings_sync_util {
 
 namespace {
 
@@ skipping 79 matching lines @@
     const std::string& extension_id,
     const std::string& key,
     syncer::ModelType type) {
   base::DictionaryValue no_value;
   return syncer::SyncChange(
       FROM_HERE,
       syncer::SyncChange::ACTION_DELETE,
       CreateData(extension_id, key, no_value, type));
 }
 
+syncer::SyncableService* GetSyncableService(content::BrowserContext* context,
+                                            syncer::ModelType type) {

[Devlin, 2014/03/05 19:02:55]

There used to be a DCHECK(OnFileThread) here (back when it was
SettingsFrontend::GetBackendForSync).  Is it no longer needed?

[James Cook, 2014/03/05 23:14:28]

Added back.  (I was relying on the DCHECK in
SyncValueStoreCache::GetSyncableService() but it's clearer to be explicit here.)

+  DCHECK(type == syncer::APP_SETTINGS || type == syncer::EXTENSION_SETTINGS);
+  SettingsFrontend* frontend = SettingsFrontend::Get(context);
+  SyncValueStoreCache* sync_cache = static_cast<SyncValueStoreCache*>(
+      frontend->GetValueStoreCache(settings_namespace::SYNC));
+  return sync_cache->GetSyncableService(type);
+}
+
 }  // namespace settings_sync_util
 
 }  // namespace extensions