ProtectorService supports multiple change instances.

chrome/browser/protector/default_search_provider_change_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 "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/protector/histograms.h"
 #include "chrome/browser/protector/mock_protector_service.h"
@@ skipping 465 matching lines @@
   scoped_ptr<BaseSettingChange> change(
       CreateDefaultSearchProviderChange(current_url, backup_url));
   ASSERT_TRUE(change.get());
   ASSERT_TRUE(change->Init(browser()->profile()));
 
   // Verify that backup is active.
   EXPECT_EQ(FindTemplateURL(http_example_info),
             turl_service_->GetDefaultSearchProvider());
 
   // Verify that changing search provider externally dismissed the change.
-  EXPECT_CALL(*mock_protector_service_, DismissChange());
+  EXPECT_CALL(*mock_protector_service_, DismissChange(change.get()));
   AddAndSetDefault(new_url);
 }
 
 IN_PROC_BROWSER_TEST_F(DefaultSearchProviderChangeTest,
                        CurrentSearchProviderRemovedByUser) {
   // Current search provider is removed by user while the error is active.
   // Setup is the same as in BackupValid test case.
   TemplateURL* backup_url =
       MakeTemplateURL(example_info, ASCIIToUTF16("a"), http_example_info);
   TemplateURL* current_url =
@@ skipping 25 matching lines @@
   EXPECT_EQ(FindTemplateURL(http_example_info),
             turl_service_->GetDefaultSearchProvider());
 
   // Discard does nothing - backup was already active.
   change->Discard(browser());
   EXPECT_EQ(FindTemplateURL(http_example_info),
             turl_service_->GetDefaultSearchProvider());
 }
 
 }  // namespace protector