MD Downloads: reset list tracker when renderer crashes

chrome/browser/ui/webui/md_downloads/md_downloads_dom_handler.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_UI_WEBUI_MD_DOWNLOADS_MD_DOWNLOADS_DOM_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_MD_DOWNLOADS_MD_DOWNLOADS_DOM_HANDLER_H_
 
 #include <stdint.h>
 
 #include <set>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/download/download_danger_prompt.h"
 #include "chrome/browser/ui/webui/md_downloads/downloads_list_tracker.h"
+#include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 namespace base {
 class ListValue;
 }
 
 namespace content {
 class DownloadItem;
 class DownloadManager;
-class RenderViewHost;
 class WebContents;
 class WebUI;
 }
 
 // The handler for Javascript messages related to the "downloads" view,
 // also observes changes to the download manager.
-class MdDownloadsDOMHandler : public content::WebUIMessageHandler {
+class MdDownloadsDOMHandler : public content::WebContentsObserver,
+                              public content::WebUIMessageHandler {
  public:
   MdDownloadsDOMHandler(content::DownloadManager* download_manager,
                         content::WebUI* web_ui);
   ~MdDownloadsDOMHandler() override;
 
   // WebUIMessageHandler implementation.
   void RegisterMessages() override;
   void OnJavascriptDisallowed() override;
 
+  // WebContentsObserver implementation.
+  void RenderProcessGone(base::TerminationStatus status) override;
+
   // Callback for the "getDownloads" message.
   void HandleGetDownloads(const base::ListValue* args);
 
   // Callback for the "openFile" message - opens the file in the shell.
   void HandleOpenFile(const base::ListValue* args);
 
   // Callback for the "drag" message - initiates a file object drag.
   void HandleDrag(const base::ListValue* args);
 
   // Callback for the "saveDangerous" message - specifies that the user
@@ skipping 83 matching lines @@
 
   // IDs of downloads to remove when this handler gets deleted.
   std::vector<IdSet> removals_;
 
   base::WeakPtrFactory<MdDownloadsDOMHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MdDownloadsDOMHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_MD_DOWNLOADS_MD_DOWNLOADS_DOM_HANDLER_H_