MD Downloads: track downloads in C++, dispatch discrete JS updates

chrome/browser/ui/webui/md_downloads/md_downloads_ui.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/md_downloads/md_downloads_ui.h"
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/singleton.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_piece.h"
@@ skipping 124 matching lines @@
 ///////////////////////////////////////////////////////////////////////////////
 //
 // MdDownloadsUI
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 MdDownloadsUI::MdDownloadsUI(content::WebUI* web_ui) : WebUIController(web_ui) {
   Profile* profile = Profile::FromWebUI(web_ui);
   DownloadManager* dlm = BrowserContext::GetDownloadManager(profile);
 
-  MdDownloadsDOMHandler* handler = new MdDownloadsDOMHandler(dlm);
-  web_ui->AddMessageHandler(handler);
+  handler_ = new MdDownloadsDOMHandler(dlm, web_ui);
+  web_ui->AddMessageHandler(handler_);
 
   // Set up the chrome://downloads/ source.
   content::WebUIDataSource* source = CreateDownloadsUIHTMLSource(profile);
   content::WebUIDataSource::Add(profile, source);
 #if defined(ENABLE_THEMES)
   ThemeSource* theme = new ThemeSource(profile);
   content::URLDataSource::Add(profile, theme);
 #endif
 }
 
 // static
 base::RefCountedMemory* MdDownloadsUI::GetFaviconResourceBytes(
     ui::ScaleFactor scale_factor) {
   return ResourceBundle::GetSharedInstance().
       LoadDataResourceBytesForScale(IDR_DOWNLOADS_FAVICON, scale_factor);
 }
+
+void MdDownloadsUI::RenderViewReused(
+    content::RenderViewHost* render_view_host) {
+  handler_->RenderViewReused(render_view_host);
+}