Revert of NTP Zombie Code Slayer Part IV: Most Visited

chrome/browser/search/thumbnail_source.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_BROWSER_SEARCH_THUMBNAIL_SOURCE_H_
-#define CHROME_BROWSER_SEARCH_THUMBNAIL_SOURCE_H_
-
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-#include "content/public/browser/url_data_source.h"
-
-class Profile;
-
-namespace base {
-class RefCountedMemory;
-}
-
-namespace thumbnails {
-class ThumbnailService;
-}
-
-// ThumbnailSource is the gateway between network-level chrome: requests for
-// thumbnails and the history/top-sites backend that serves these.
-class ThumbnailSource : public content::URLDataSource {
- public:
-  ThumbnailSource(Profile* profile, bool capture_thumbnails);
-
-  // content::URLDataSource implementation.
-  std::string GetSource() const override;
-  void StartDataRequest(
-      const std::string& path,
-      int render_process_id,
-      int render_frame_id,
-      const content::URLDataSource::GotDataCallback& callback) override;
-  std::string GetMimeType(const std::string& path) const override;
-  base::MessageLoop* MessageLoopForRequestPath(
-      const std::string& path) const override;
-  bool ShouldServiceRequest(const net::URLRequest* request) const override;
-
- private:
-  ~ThumbnailSource() override;
-
-  // Raw PNG representation of the thumbnail to show when the thumbnail
-  // database doesn't have a thumbnail for a webpage.
-  scoped_refptr<base::RefCountedMemory> default_thumbnail_;
-
-  // ThumbnailService.
-  scoped_refptr<thumbnails::ThumbnailService> thumbnail_service_;
-
-  // Indicate that, when a URL for which we don't have a thumbnail is requested
-  // from this source, then Chrome should capture a thumbnail next time it
-  // navigates to this URL. This is useful when the thumbnail URLs are generated
-  // by an external service rather than TopSites, so Chrome can learn about the
-  // URLs for which it should get thumbnails. Sources that capture thumbnails
-  // are also be more lenient when matching thumbnail URLs by checking for
-  // existing thumbnails in the database that contain a URL matching the prefix
-  // of the requested URL.
-  const bool capture_thumbnails_;
-
-  DISALLOW_COPY_AND_ASSIGN(ThumbnailSource);
-};
-
-#endif  // CHROME_BROWSER_SEARCH_THUMBNAIL_SOURCE_H_