First fix to minimize copying of image data.

chrome/browser/dom_ui/dom_ui_theme_source.h

 // Copyright (c) 2009 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_DOM_UI_DOM_UI_THEME_SOURCE_H_
 #define CHROME_BROWSER_DOM_UI_DOM_UI_THEME_SOURCE_H_
 
 #include <string>
 
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 
 class Profile;
 
 // ThumbnailSource is the gateway between network-level chrome:
 // requests for thumbnails and the history backend that serves these.
 class DOMUIThemeSource : public ChromeURLDataManager::DataSource {
  public:
   explicit DOMUIThemeSource(Profile* profile);
 
   // Called when the network layer has requested a resource underneath
   // the path we registered.
   virtual void StartDataRequest(const std::string& path, int request_id);
   virtual std::string GetMimeType(const std::string& path) const;
 
-  virtual void SendResponse(int request_id, RefCountedBytes* data);
+  virtual void SendResponse(int request_id, RefCountedMemory* data);
 
   virtual MessageLoop* MessageLoopForRequestPath(const std::string& path) const;
 
  private:
   // Populate new_tab_css_ and new_incognito_tab_css.  These must be called
   // from the UI thread because they involve profile and theme access.
   //
   // A new DOMUIThemeSource object is used for each new tab page instance
   // and each reload of an existing new tab page, so there is no concern about
   // cached data becoming stale.
@@ skipping 17 matching lines @@
   // The content to be served by SendNewTabCSS, stored by InitNewTabCSS and
   // InitNewIncognitoTabCSS.
   std::string new_tab_css_;
   std::string new_incognito_tab_css_;
 
   Profile* profile_;
   DISALLOW_COPY_AND_ASSIGN(DOMUIThemeSource);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_DOM_UI_THEME_SOURCE_H_