chrome: Cleanup class/struct forward declarations

chrome/browser/ui/views/apps/chrome_native_app_window_views.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 CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_H_
 #define CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "extensions/components/native_app_window/native_app_window_views.h"
 
-namespace apps {
-class AppWindowFrameView;
-}
-
 class ExtensionKeybindingRegistryViews;
 
 class ChromeNativeAppWindowViews
     : public native_app_window::NativeAppWindowViews {
  public:
   ChromeNativeAppWindowViews();
   ~ChromeNativeAppWindowViews() override;
 
   SkRegion* shape() { return shape_.get(); }
 
@@ skipping 58 matching lines @@
   gfx::Size preferred_size_;
 
   // The class that registers for keyboard shortcuts for extension commands.
   std::unique_ptr<ExtensionKeybindingRegistryViews>
       extension_keybinding_registry_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeNativeAppWindowViews);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_H_