Fix ExtensionServiceTest.ClearExtensionData flakiness

chrome/browser/policy/policy_browsertest.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 <algorithm>
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 691 matching lines @@
     }
     return NULL;
   }
 
   void UninstallExtension(const std::string& id, bool expect_success) {
     content::WindowedNotificationObserver observer(
         expect_success ? chrome::NOTIFICATION_EXTENSION_UNINSTALLED_DEPRECATED
                        : chrome::NOTIFICATION_EXTENSION_UNINSTALL_NOT_ALLOWED,
         content::NotificationService::AllSources());
     extension_service()->UninstallExtension(
-        id, extensions::UNINSTALL_REASON_FOR_TESTING, NULL);
+        id,
+        extensions::UNINSTALL_REASON_FOR_TESTING,
+        base::Bind(&base::DoNothing),
+        NULL);
     observer.Wait();
   }
 
   void UpdateProviderPolicy(const PolicyMap& policy) {
     provider_.UpdateChromePolicy(policy);
     DCHECK(base::MessageLoop::current());
     base::RunLoop loop;
     loop.RunUntilIdle();
   }
 
@@ skipping 2452 matching lines @@
   EXPECT_TRUE(content::ExecuteScriptAndExtractBool(
       browser2->tab_strip_model()->GetActiveWebContents(),
       "domAutomationController.send(window.showModalDialog !== undefined);",
       &result));
   EXPECT_TRUE(result);
 }
 
 #endif  // !defined(CHROME_OS)
 
 }  // namespace policy