extensions: Cleanup class/struct fwd declarations

extensions/browser/extension_host.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_EXTENSION_HOST_H_
 #define EXTENSIONS_BROWSER_EXTENSION_HOST_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <set>
 #include <string>
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/timer/elapsed_timer.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "extensions/browser/deferred_start_render_host.h"
 #include "extensions/browser/extension_function_dispatcher.h"
 #include "extensions/browser/extension_registry_observer.h"
 #include "extensions/common/stack_frame.h"
 #include "extensions/common/view_type.h"
 
-class PrefsTabHelper;
-
 namespace content {
 class BrowserContext;
 class RenderProcessHost;
-class RenderWidgetHostView;
 class SiteInstance;
 }
 
 namespace extensions {
 class Extension;
 class ExtensionHostDelegate;
 class ExtensionHostObserver;
 class ExtensionHostQueue;
-class WindowController;
 
 // This class is the browser component of an extension component's RenderView.
 // It handles setting up the renderer process, if needed, with special
 // privileges available to extensions.  It may have a view to be shown in the
 // browser UI, or it may be hidden.
 //
 // If you are adding code that only affects visible extension views (and not
 // invisible background pages) you should add it to ExtensionViewHost.
 class ExtensionHost : public DeferredStartRenderHost,
                       public content::WebContentsDelegate,
@@ skipping 167 matching lines @@
   base::ObserverList<ExtensionHostObserver> observer_list_;
   base::ObserverList<DeferredStartRenderHostObserver>
       deferred_start_render_host_observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_HOST_H_