First fix to minimize copying of image data.

chrome/browser/dom_ui/dom_ui_theme_source.cc

 // 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.
 
 #include "chrome/browser/dom_ui/dom_ui_theme_source.h"
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "app/theme_provider.h"
 #include "base/message_loop.h"
@@ skipping 72 matching lines @@
   std::string uncached_path = StripQueryParams(path);
 
   if (uncached_path == kNewTabCSSPath ||
       uncached_path == kNewIncognitoTabCSSPath) {
     return "text/css";
   }
 
   return "image/png";
 }
 
-void DOMUIThemeSource::SendResponse(int request_id, RefCountedBytes* data) {
+void DOMUIThemeSource::SendResponse(int request_id, RefCountedMemory* data) {
   ChromeURLDataManager::DataSource::SendResponse(request_id, data);
 }
 
 MessageLoop* DOMUIThemeSource::MessageLoopForRequestPath(
     const std::string& path) const {
   std::string uncached_path = StripQueryParams(path);
 
   if (uncached_path == kNewTabCSSPath ||
       uncached_path == kNewIncognitoTabCSSPath) {
     // All of the operations that need to be on the UI thread for these
@@ skipping 137 matching lines @@
   std::copy(css_string.begin(), css_string.end(), css_bytes->data.begin());
 
   // Send.
   SendResponse(request_id, css_bytes);
 }
 
 void DOMUIThemeSource::SendThemeBitmap(int request_id, int resource_id) {
   ThemeProvider* tp = profile_->GetThemeProvider();
   DCHECK(tp);
 
-  std::vector<unsigned char> png_bytes;
-  if (tp->GetRawData(resource_id, &png_bytes)) {
-    scoped_refptr<RefCountedBytes> image_data =
-        new RefCountedBytes(png_bytes);
-    SendResponse(request_id, image_data);
-  } else {
-    SendResponse(request_id, NULL);
-  }
+  scoped_refptr<RefCountedMemory> image_data(tp->GetRawData(resource_id));
+  SendResponse(request_id, image_data);
 }
 
 std::string DOMUIThemeSource::GetNewTabBackgroundCSS(bool bar_attached) {
   int alignment;
   profile_->GetThemeProvider()->GetDisplayProperty(
       BrowserThemeProvider::NTP_BACKGROUND_ALIGNMENT, &alignment);
 
   // TODO(glen): This is a quick workaround to hide the notused.png image when
   // no image is provided - we don't have time right now to figure out why
   // this is painting as white.
@@ skipping 27 matching lines @@
   return BrowserThemeProvider::AlignmentToString(alignment);
 }
 
 std::string DOMUIThemeSource::GetNewTabBackgroundTilingCSS() {
   int repeat_mode;
   profile_->GetThemeProvider()->GetDisplayProperty(
       BrowserThemeProvider::NTP_BACKGROUND_TILING, &repeat_mode);
   return BrowserThemeProvider::TilingToString(repeat_mode);
 }