Extension Settings API: make it so that when changes received from Sync fail to

chrome/browser/extensions/settings/settings_backend.h

Index: chrome/browser/extensions/settings/settings_backend.h
diff --git a/chrome/browser/extensions/settings/settings_backend.h b/chrome/browser/extensions/settings/settings_backend.h
index 1c6366fc5c2ce234aa9355e5a9cf9317f7eed7c9..c9365d8bf65ecea0f043fe984836db638f5307ed 100644
--- a/chrome/browser/extensions/settings/settings_backend.h
+++ b/chrome/browser/extensions/settings/settings_backend.h
@@ -38,12 +38,7 @@ class SettingsBackend : public SyncableService {
 
   // Gets a weak reference to the storage area for a given extension.
   // Must be run on the FILE thread.
-  //
-  // By default this will be an SettingsLeveldbStorage, but on
-  // failure to create a leveldb instance will fall back to
-  // InMemorySettingsStorage.
-  SettingsStorage* GetStorage(
-      const std::string& extension_id) const;
+  SettingsStorage* GetStorage(const std::string& extension_id) const;
 
   // Deletes all setting data for an extension.  Call on the FILE thread.
   void DeleteStorage(const std::string& extension_id);
@@ -72,6 +67,9 @@ class SettingsBackend : public SyncableService {
   // installed extensions.
   std::set<std::string> GetKnownExtensionIDs() const;
 
+  // Disable the syncing of the storage area for |extension_id|.
+  void DisableSyncForExtension(const std::string& extension_id) const;
+
   // The Factory to use for creating leveldb storage areas.  Not owned.
   SettingsStorageFactory* const storage_factory_;