Don't derive from ChromeURLDataManager::DataSource, and instead have these classes implement a dele…

chrome/browser/ui/webui/ntp/thumbnail_source.cc

 // 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.
 
 #include "chrome/browser/ui/webui/ntp/thumbnail_source.h"
 
 #include "base/callback.h"
 #include "base/message_loop.h"
 #include "base/memory/ref_counted_memory.h"
 #include "chrome/browser/thumbnails/thumbnail_service.h"
 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/webui/chrome_url_data_manager.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 
+// Set ThumbnailService now as Profile isn't thread safe.
 ThumbnailSource::ThumbnailSource(Profile* profile)
-    : DataSource(chrome::kChromeUIThumbnailHost, MessageLoop::current()),
-      // Set ThumbnailService now as Profile isn't thread safe.
-      thumbnail_service_(ThumbnailServiceFactory::GetForProfile(profile)) {
+    : thumbnail_service_(ThumbnailServiceFactory::GetForProfile(profile)) {
 }
 
 ThumbnailSource::~ThumbnailSource() {
 }
 
+std::string ThumbnailSource::GetSource() {
+  return chrome::kChromeUIThumbnailHost;
+}
+
 void ThumbnailSource::StartDataRequest(const std::string& path,
                                        bool is_incognito,
                                        int request_id) {
   scoped_refptr<base::RefCountedMemory> data;
   if (thumbnail_service_->GetPageThumbnail(GURL(path), &data)) {
     // We have the thumbnail.
-    SendResponse(request_id, data.get());
+    url_data_source()->SendResponse(request_id, data.get());
   } else {
     SendDefaultThumbnail(request_id);
   }
 }
 
 std::string ThumbnailSource::GetMimeType(const std::string&) const {
   // We need to explicitly return a mime type, otherwise if the user tries to
   // drag the image they get no extension.
   return "image/png";
 }
 
 MessageLoop* ThumbnailSource::MessageLoopForRequestPath(
     const std::string& path) const {
   // TopSites can be accessed from the IO thread.
   return thumbnail_service_.get() ?
-      NULL : DataSource::MessageLoopForRequestPath(path);
+      NULL : content::URLDataSourceDelegate::MessageLoopForRequestPath(path);
 }
 
 void ThumbnailSource::SendDefaultThumbnail(int request_id) {
-  SendResponse(request_id, default_thumbnail_);
+  url_data_source()->SendResponse(request_id, default_thumbnail_);
 }