Fix ExtensionServiceTest.ClearExtensionData flakiness

chrome/browser/extensions/shared_module_service_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 "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_service_test_base.h"
@@ skipping 128 matching lines @@
   std::string extension_id = id_util::GenerateId("extension_id");
   // Create and install an extension that imports our new module.
   scoped_refptr<Extension> importing_extension =
       CreateExtensionImportingModule(shared_module->id(), extension_id, "1.0");
   EXPECT_TRUE(InstallExtension(importing_extension, false));
 
   // Uninstall the extension that imports our module.
   base::string16 error;
   service()->UninstallExtension(importing_extension->id(),
                                 extensions::UNINSTALL_REASON_FOR_TESTING,
+                                base::Bind(&base::DoNothing),
                                 &error);
   EXPECT_TRUE(error.empty());
 
   // Since the module was only referenced by that single extension, it should
   // have been uninstalled as a side-effect of uninstalling the extension that
   // depended upon it.
   EXPECT_FALSE(registry()->GetExtensionById(shared_module->id(),
                                             ExtensionRegistry::EVERYTHING));
 }
 
@@ skipping 100 matching lines @@
 
   // Try to install an extension with an ID that is not whitelisted.
   scoped_refptr<Extension> nonwhitelisted_extension =
       CreateExtensionImportingModule(shared_module->id(),
                                      nonwhitelisted_id,
                                      "1.0");
   EXPECT_FALSE(InstallExtension(nonwhitelisted_extension, false));
 }
 
 }  // namespace extensions