Implementing chrome://thumbnails page to view URLs in TopSites and cached thumbnails.

chrome/browser/ui/webui/ntp/thumbnail_list_source.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2013 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_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
-#define CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
+#ifndef CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_LIST_SOURCE_H_
+#define CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_LIST_SOURCE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/history/history_types.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 {
+// ThumbnailListSource renders a webpage to list all thumbnails stored in
+// TopSites, along with all associated URLs. The thumbnail images are embedded
+// into the HTML via Base64, so we can easily produce a dump of TopSites and
+// the thumbnails it stores.
+class ThumbnailListSource : public content::URLDataSource {
  public:
-  ThumbnailSource(Profile* profile, bool prefix_match);
+  explicit ThumbnailListSource(Profile* profile);
 
   // content::URLDataSource implementation.
   virtual std::string GetSource() const OVERRIDE;
   virtual void StartDataRequest(
       const std::string& path,
       int render_process_id,
       int render_view_id,
       const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
   virtual std::string GetMimeType(const std::string& path) const OVERRIDE;
   virtual base::MessageLoop* MessageLoopForRequestPath(
       const std::string& path) const OVERRIDE;
   virtual bool ShouldServiceRequest(
       const net::URLRequest* request) const OVERRIDE;
 
  private:
-  virtual ~ThumbnailSource();
+  virtual ~ThumbnailListSource();
 
-  // 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_;
+  void OnMostVisitedURLsAvailable(
+    const content::URLDataSource::GotDataCallback& callback,
+    const history::MostVisitedURLList& mvurl_list);
 
   // ThumbnailService.
   scoped_refptr<thumbnails::ThumbnailService> thumbnail_service_;
 
   // Only used when servicing requests on the UI thread.
   Profile* const profile_;
 
-  // If an exact thumbnail URL match fails, specifies whether or not to try
-  // harder by matching the query thumbnail URL as URL prefix. This affects
-  // GetSource().
-  const bool prefix_match_;
+  // For callbacks may be run after destruction.
+  base::WeakPtrFactory<ThumbnailListSource> weak_ptr_factory_;
 
-  DISALLOW_COPY_AND_ASSIGN(ThumbnailSource);
+  DISALLOW_COPY_AND_ASSIGN(ThumbnailListSource);
 };
 
-#endif  // CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
+
+#endif  // CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_LIST_SOURCE_H_