Fix ExtensionServiceTest.ClearExtensionData flakiness

chrome/browser/extensions/extension_gcm_app_handler_unittest.cc

 // Copyright 2014 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/extension_gcm_app_handler.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 317 matching lines @@
     extension_service_->DisableExtension(
         extension->id(), Extension::DISABLE_USER_ACTION);
   }
 
   void EnableExtension(const Extension* extension) {
     extension_service_->EnableExtension(extension->id());
   }
 
   void UninstallExtension(const Extension* extension) {
     extension_service_->UninstallExtension(
-        extension->id(), extensions::UNINSTALL_REASON_FOR_TESTING, NULL);
+        extension->id(),
+        extensions::UNINSTALL_REASON_FOR_TESTING,
+        base::Bind(&base::DoNothing),
+        NULL);
   }
 
   void SignIn(const std::string& username) {
     signin_manager_->SignIn(username);
     waiter_.PumpIOLoop();
   }
 
   void SignOut() {
     signin_manager_->SignOut(signin_metrics::SIGNOUT_TEST);
     waiter_.PumpIOLoop();
@@ skipping 136 matching lines @@
 
   // App handler is removed when the extension is updated to the version that
   // has GCM permission removed.
   UpdateExtension(extension, "good2.crx");
   waiter()->PumpUILoop();
   EXPECT_TRUE(gcm_app_handler()->app_handler_count_drop_to_zero());
   EXPECT_FALSE(HasAppHandlers(extension->id()));
 }
 
 }  // namespace extensions