Fix for pixelated icons in extension install ui on 2x scale.

chrome/common/extensions/extension.h

 // Copyright (c) 2012 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_COMMON_EXTENSIONS_EXTENSION_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_H_
 
 #include <algorithm>
 #include <iosfwd>
 #include <map>
@@ skipping 427 matching lines @@
   // Given an icon_path and icon size, read it if present and decode it into
   // result. In the browser process, this will DCHECK if not called on the
   // file thread. To easily load extension images on the UI thread, see
   // ImageLoadingTracker.
   static void DecodeIconFromPath(const FilePath& icon_path,
                                  int icon_size,
                                  scoped_ptr<SkBitmap>* result);
 
   // Returns the default extension/app icon (for extensions or apps that don't
   // have one).
-  static const SkBitmap& GetDefaultIcon(bool is_app);
+  static const gfx::ImageSkia& GetDefaultIcon(bool is_app);
 
   // Returns the base extension url for a given |extension_id|.
   static GURL GetBaseURLFromExtensionId(const std::string& extension_id);
 
   // Adds an extension to the scripting whitelist. Used for testing only.
   static void SetScriptingWhitelist(const ScriptingWhitelist& whitelist);
   static const ScriptingWhitelist* GetScriptingWhitelist();
 
   // Parses the host and api permissions from the specified permission |key|
   // from |manifest_|.
@@ skipping 772 matching lines @@
 
   UpdatedExtensionPermissionsInfo(
       const Extension* extension,
       const PermissionSet* permissions,
       Reason reason);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_H_