chrome: Cleanup class/struct forward declarations

chrome/browser/apps/app_shim/extension_app_shim_handler_mac.h

 // Copyright 2013 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_APPS_APP_SHIM_EXTENSION_APP_SHIM_HANDLER_MAC_H_
 #define CHROME_BROWSER_APPS_APP_SHIM_EXTENSION_APP_SHIM_HANDLER_MAC_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "apps/app_lifetime_monitor.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/apps/app_shim/app_shim_handler_mac.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/app_window/app_window_registry.h"
 
 class Profile;
 
 namespace base {
 class FilePath;
 }
 
-namespace content {
-class WebContents;
-}
-
 namespace extensions {
 class AppWindow;
 class Extension;
 }
 
 namespace apps {
 
 // This app shim handler that handles events for app shims that correspond to an
 // extension.
 class ExtensionAppShimHandler : public AppShimHandler,
@@ skipping 149 matching lines @@
   content::NotificationRegistrar registrar_;
 
   base::WeakPtrFactory<ExtensionAppShimHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAppShimHandler);
 };
 
 }  // namespace apps
 
 #endif  // CHROME_BROWSER_APPS_APP_SHIM_EXTENSION_APP_SHIM_HANDLER_MAC_H_