chrome: Cleanup class/struct forward declarations

chrome/browser/ui/ime/ime_window.h

 // Copyright 2016 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_IME_IME_WINDOW_H_
 #define CHROME_BROWSER_UI_IME_IME_WINDOW_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 14 matching lines @@
 namespace content {
 class RenderFrameHost;
 class WebContents;
 }
 
 namespace extensions {
 class Extension;
 }
 
 namespace gfx {
-class Image;
 class Rect;
 }
 
 namespace ui {
 
 class ImeNativeWindow;
 class ImeWindowObserver;
 
 // The implementation for the IME window.
 // This is used in the IME extension API.
@@ skipping 95 matching lines @@
   ImeNativeWindow* native_window_;  // Weak, it does self-destruction.
 
   base::ObserverList<ImeWindowObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ImeWindow);
 };
 
 }  // namespace ui
 
 #endif  // CHROME_BROWSER_UI_IME_IME_WINDOW_H_