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

chrome/browser/extensions/api/storage/settings_sync_util.cc

Index: chrome/browser/extensions/api/storage/settings_sync_util.cc
diff --git a/chrome/browser/extensions/api/storage/settings_sync_util.cc b/chrome/browser/extensions/api/storage/settings_sync_util.cc
index b974aa3f619ed30642362b13f163d86e2edf8479..b7a598a5ecd2dfa548b7c3c6a3ad5ee2ee05dab5 100644
--- a/chrome/browser/extensions/api/storage/settings_sync_util.cc
+++ b/chrome/browser/extensions/api/storage/settings_sync_util.cc
@@ -6,6 +6,8 @@
 
 #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"
@@ -105,6 +107,15 @@ syncer::SyncChange CreateDelete(
       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