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

chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc

Index: chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
diff --git a/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc b/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
index 3e8ec98e282bdbe79140c9f3da0c35d03df805d9..95d3a4e582f41f1126a7b8db1a013ba4f64a258c 100644
--- a/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
+++ b/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
@@ -142,8 +142,8 @@ 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);
@@ -160,3 +160,8 @@ base::RefCountedMemory* MdDownloadsUI::GetFaviconResourceBytes(
   return ResourceBundle::GetSharedInstance().
       LoadDataResourceBytesForScale(IDR_DOWNLOADS_FAVICON, scale_factor);
 }
+
+void MdDownloadsUI::RenderViewReused(
+    content::RenderViewHost* render_view_host) {
+  handler_->RenderViewReused(render_view_host);
+}