chrome: Cleanup class/struct forward declarations

chrome/browser/ui/webui/options/preferences_browsertest.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_OPTIONS_PREFERENCES_BROWSERTEST_H_
 #define CHROME_BROWSER_UI_WEBUI_OPTIONS_PREFERENCES_BROWSERTEST_H_
 
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "components/policy/core/common/mock_configuration_policy_provider.h"
 #include "components/policy/core/common/policy_types.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "components/prefs/pref_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace base {
 class DictionaryValue;
 class Value;
 }
 
 namespace content {
-class NotificationDetails;
-class NotificationSource;
 class RenderViewHost;
 }
 
 // Tests verifying that the JavaScript Preferences class, the underlying C++
 // CoreOptionsHandler and the specialized classes handling Chrome OS device and
 // proxy prefs behave correctly.
 class PreferencesBrowserTest : public InProcessBrowserTest {
  public:
   PreferencesBrowserTest();
   ~PreferencesBrowserTest() override;
@@ skipping 147 matching lines @@
   std::vector<std::string> pref_names_;
   std::vector<std::string> policy_names_;
   ScopedVector<base::Value> default_values_;
   ScopedVector<base::Value> non_default_values_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PreferencesBrowserTest);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_OPTIONS_PREFERENCES_BROWSERTEST_H_