Cleanup: Remove unneeded forward declarations from various chrome subdirectories.

chrome/test/base/testing_browser_process.h

 // Copyright (c) 2011 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.
 
 // An implementation of BrowserProcess for unit tests that fails for most
 // services. By preventing creation of services, we reduce dependencies and
 // keep the profile clean. Clients of this class must handle the NULL return
 // value, however.
 
 #ifndef CHROME_TEST_BASE_TESTING_BROWSER_PROCESS_H_
 #define CHROME_TEST_BASE_TESTING_BROWSER_PROCESS_H_
 #pragma once
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "content/browser/notification_service_impl.h"
 
 class BackgroundModeManager;
 class CRLSetFetcher;
 class IOThread;
 class GoogleURLTracker;
 class MHTMLGenerationManager;
 class NotificationUIManager;
 class PrefService;
 class WatchDogThread;
 
-namespace base {
-class WaitableEvent;
-}
-
 namespace policy {
 class BrowserPolicyConnector;
 }
 
 namespace prerender {
 class PrerenderTracker;
 }
 
 namespace ui {
 class Clipboard;
@@ skipping 101 matching lines @@
   scoped_ptr<NotificationUIManager> notification_ui_manager_;
   scoped_ptr<printing::BackgroundPrintingManager> background_printing_manager_;
   scoped_ptr<prerender::PrerenderTracker> prerender_tracker_;
   IOThread* io_thread_;
   scoped_ptr<DevToolsManager> devtools_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(TestingBrowserProcess);
 };
 
 #endif  // CHROME_TEST_BASE_TESTING_BROWSER_PROCESS_H_