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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
      6 #define CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
      7 
      8 #include <string>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/ref_counted.h"
     12 #include "content/public/browser/url_data_source.h"
     13 
     14 class Profile;
     15 
     16 namespace base {
     17 class RefCountedMemory;
     18 }
     19 
     20 namespace thumbnails {
     21 class ThumbnailService;
     22 }
     23 
     24 // ThumbnailSource is the gateway between network-level chrome: requests for
     25 // thumbnails and the history/top-sites backend that serves these.
     26 class ThumbnailSource : public content::URLDataSource {
     27  public:
     28   ThumbnailSource(Profile* profile, bool capture_thumbnails);
     29 
     30   // content::URLDataSource implementation.
     31   virtual std::string GetSource() const OVERRIDE;
     32   virtual void StartDataRequest(
     33       const std::string& path,
     34       int render_process_id,
     35       int render_view_id,
     36       const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
     37   virtual std::string GetMimeType(const std::string& path) const OVERRIDE;
     38   virtual base::MessageLoop* MessageLoopForRequestPath(
     39       const std::string& path) const OVERRIDE;
     40   virtual bool ShouldServiceRequest(
     41       const net::URLRequest* request) const OVERRIDE;
     42 
     43  private:
     44   virtual ~ThumbnailSource();
     45 
     46   // Raw PNG representation of the thumbnail to show when the thumbnail
     47   // database doesn't have a thumbnail for a webpage.
     48   scoped_refptr<base::RefCountedMemory> default_thumbnail_;
     49 
     50   // ThumbnailService.
     51   scoped_refptr<thumbnails::ThumbnailService> thumbnail_service_;
     52 
     53   // Only used when servicing requests on the UI thread.
     54   Profile* const profile_;
     55 
     56   // Indicate that, when a URL for which we don't have a thumbnail is requested
     57   // from this source, then Chrome should capture a thumbnail next time it
     58   // navigates to this URL. This is useful when the thumbnail URLs are generated
     59   // by an external service rather than TopSites, so Chrome can learn about the
     60   // URLs for which it should get thumbnails. Sources that capture thumbnails
     61   // are also be more lenient when matching thumbnail URLs by checking for
     62   // existing thumbnails in the database that contain a URL matching the prefix
     63   // of the requested URL.
     64   const bool capture_thumbnails_;
     65 
     66   DISALLOW_COPY_AND_ASSIGN(ThumbnailSource);
     67 };
     68 
     69 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
     70