chrome: Cleanup class/struct forward declarations

chrome/browser/ui/views/apps/chrome_native_app_window_views_aura.h

 // Copyright 2015 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_AURA_H_
 #define CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_AURA_H_
 
 #include <memory>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/views/apps/chrome_native_app_window_views.h"
 
-namespace apps {
-class AppWindowFrameView;
-}
-
 // Aura-specific parts of ChromeNativeAppWindowViews. This is used directly on
 // Linux and Windows, and is the base class for the Ash specific class used on
 // ChromeOS.
 class ChromeNativeAppWindowViewsAura : public ChromeNativeAppWindowViews {
  public:
   ChromeNativeAppWindowViewsAura();
   ~ChromeNativeAppWindowViewsAura() override;
 
  protected:
   ui::WindowShowState GetRestorableState(
@@ skipping 14 matching lines @@
   void UpdateShape(std::unique_ptr<SkRegion> region) override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ShapedAppWindowTargeterTest,
                            ResizeInsetsWithinBounds);
 
   DISALLOW_COPY_AND_ASSIGN(ChromeNativeAppWindowViewsAura);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_AURA_H_