content: Cleanup class/struct forward declarations

content/browser/web_contents/web_contents_impl.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 CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <stdint.h>
 
 #include <functional>
@@ skipping 41 matching lines @@
 struct ViewHostMsg_DateTimeDialogValue_Params;
 
 namespace service_manager {
 class InterfaceProvider;
 }
 
 namespace content {
 class BrowserPluginEmbedder;
 class BrowserPluginGuest;
 class DateTimeChooserAndroid;
-class DownloadItem;
 class FindRequestManager;
 class HostZoomMapObserver;
 class InterstitialPageImpl;
 class JavaScriptDialogManager;
 class LoaderIOThreadNotifier;
 class ManifestManagerHost;
 class MediaWebContentsObserver;
 class PluginContentOriginWhitelist;
-class PowerSaveBlocker;
 class RenderViewHost;
 class RenderViewHostDelegateView;
 class RenderWidgetHostImpl;
 class RenderWidgetHostInputEventRouter;
 class SavePackage;
 class ScreenOrientationDispatcherHost;
 class SiteInstance;
 class TestWebContents;
 class TextInputManager;
 class WakeLockServiceContext;
@@ skipping 1370 matching lines @@
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendZone);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_