Notify GCMAppHandlers when the store is reset, so they clear cached IDs

chrome/browser/extensions/extension_gcm_app_handler.cc

Index: chrome/browser/extensions/extension_gcm_app_handler.cc
diff --git a/chrome/browser/extensions/extension_gcm_app_handler.cc b/chrome/browser/extensions/extension_gcm_app_handler.cc
index 4a7cc24bff70f0866dce8d85c4af45cb6455435b..c4526cdd930d6e7c9a21fb5fea088d473b451f8a 100644
--- a/chrome/browser/extensions/extension_gcm_app_handler.cc
+++ b/chrome/browser/extensions/extension_gcm_app_handler.cc
@@ -68,6 +68,11 @@ void ExtensionGCMAppHandler::ShutdownHandler() {
   js_event_router_.reset();
 }
 
+void ExtensionGCMAppHandler::OnStoreReset() {
+  // TODO(crbug.com/661660): Notify the extension somehow that its registration
+  // was invalidated and deleted?
+}
+
 void ExtensionGCMAppHandler::OnMessage(const std::string& app_id,
                                        const gcm::IncomingMessage& message) {
   js_event_router_->OnMessage(app_id, message);