chrome: Cleanup class/struct forward declarations

chrome/browser/manifest/manifest_icon_selector.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_MANIFEST_MANIFEST_ICON_SELECTOR_H_
 #define CHROME_BROWSER_MANIFEST_MANIFEST_ICON_SELECTOR_H_
 
 #include "base/macros.h"
 #include "content/public/common/manifest.h"
 #include "url/gurl.h"
 
-namespace content {
-class WebContents;
-}  // namespace content
-
-namespace IPC {
-class Message;
-}  // namespace IPC
-
-namespace gfx {
-class Screen;
-}
-
 // Selects the icon most closely matching the size constraints.  This follows
 // very basic heuristics -- improvements are welcome.
 class ManifestIconSelector {
  public:
   // Runs the algorithm to find the best matching icon in the icons listed in
   // the Manifest.
   //
   // Size is defined in Android's density-independent pixels (dp):
   // http://developer.android.com/guide/practices/screens_support.html
   // If/when this class is generalized, it may be a good idea to switch this to
@@ skipping 46 matching lines @@
 
   const int ideal_icon_size_in_px_;
   const int minimum_icon_size_in_px_;
 
   friend class ManifestIconSelectorTest;
 
   DISALLOW_COPY_AND_ASSIGN(ManifestIconSelector);
 };
 
 #endif  // CHROME_BROWSER_MANIFEST_MANIFEST_ICON_SELECTOR_H_