Fix ExtensionServiceTest.ClearExtensionData flakiness

chrome/browser/extensions/api/management/management_api.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/management/management_api.h"
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 634 matching lines @@
     // showing. Do nothing in that case.
     ExtensionRegistry* registry = ExtensionRegistry::Get(GetProfile());
     const Extension* extension = registry->GetExtensionById(
         extension_id_, ExtensionRegistry::EVERYTHING);
     if (!extension) {
       error_ = ErrorUtils::FormatErrorMessage(keys::kNoExtensionError,
                                               extension_id_);
       SendResponse(false);
     } else {
       bool success = service()->UninstallExtension(
-          extension_id_, extensions::UNINSTALL_REASON_MANAGEMENT_API, NULL);
+          extension_id_,
+          extensions::UNINSTALL_REASON_MANAGEMENT_API,
+          base::Bind(&base::DoNothing),
+          NULL);
 
       // TODO set error_ if !success
       SendResponse(success);
     }
   } else {
     error_ = ErrorUtils::FormatErrorMessage(
         keys::kUninstallCanceledError, extension_id_);
     SendResponse(false);
   }
 }
@@ skipping 337 matching lines @@
 ManagementAPI::GetFactoryInstance() {
   return g_factory.Pointer();
 }
 
 void ManagementAPI::OnListenerAdded(const EventListenerInfo& details) {
   management_event_router_.reset(new ManagementEventRouter(browser_context_));
   EventRouter::Get(browser_context_)->UnregisterObserver(this);
 }
 
 }  // namespace extensions