First fix to minimize copying of image data.

chrome/browser/dom_ui/dom_ui_thumbnail_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_thumbnail_source.h"
 
 #include "app/gfx/codec/jpeg_codec.h"
 #include "app/resource_bundle.h"
 #include "base/command_line.h"
 #include "chrome/browser/profile.h"
@@ skipping 46 matching lines @@
 void DOMUIThumbnailSource::DoDataRequest(const std::string& path,
                                          int request_id) {
   RefCountedBytes* data = NULL;
   scoped_refptr<ThumbnailStore> store_ = profile_->GetThumbnailStore();
   if (store_->GetPageThumbnail(GURL(path), &data)) {
     // Got the thumbnail.
     SendResponse(request_id, data);
   } else {
     // Don't have the thumbnail so return the default thumbnail.
     if (!default_thumbnail_.get()) {
-      default_thumbnail_ = new RefCountedBytes;
-      ResourceBundle::GetSharedInstance().LoadImageResourceBytes(
-          IDR_DEFAULT_THUMBNAIL, &default_thumbnail_->data);
+      default_thumbnail_ =
+          ResourceBundle::GetSharedInstance().LoadImageResourceBytes(
+              IDR_DEFAULT_THUMBNAIL);
     }
     SendResponse(request_id, default_thumbnail_);
   }
 }
 
 void DOMUIThumbnailSource::OnThumbnailDataAvailable(
     HistoryService::Handle request_handle,
     scoped_refptr<RefCountedBytes> data) {
   HistoryService* hs =
       profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   int request_id = cancelable_consumer_.GetClientData(hs, request_handle);
   // Forward the data along to the networking system.
   if (data.get() && !data->data.empty()) {
     SendResponse(request_id, data);
   } else {
     if (!default_thumbnail_.get()) {
-      default_thumbnail_ = new RefCountedBytes;
-      ResourceBundle::GetSharedInstance().LoadImageResourceBytes(
-          IDR_DEFAULT_THUMBNAIL, &default_thumbnail_->data);
+      default_thumbnail_ =
+          ResourceBundle::GetSharedInstance().LoadImageResourceBytes(
+              IDR_DEFAULT_THUMBNAIL);
     }
 
     SendResponse(request_id, default_thumbnail_);
   }
 }
 
 void DOMUIThumbnailSource::Observe(NotificationType type,
                                    const NotificationSource& source,
                                    const NotificationDetails& details) {
   if (type.value != NotificationType::THUMBNAIL_STORE_READY) {
     NOTREACHED();
     return;
   }
 
   // This notification is sent only once.
   registrar_.RemoveAll();
 
   for (size_t i = 0; i < pending_requests_.size(); ++i)
     DoDataRequest(pending_requests_[i].first, pending_requests_[i].second);
 
   pending_requests_.clear();
 }