Connecting webrtc-internals WebUI frontend with the backend

chrome/browser/ui/webui/media/webrtc_internals_message_handler.cc

+// 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.
+
+#include "chrome/browser/ui/webui/media/webrtc_internals_message_handler.h"
+
+#include "chrome/browser/media/chrome_webrtc_internals.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_ui.h"
+
+using content::BrowserThread;
+using media::ChromeWebRTCInternals;
+
+WebRTCInternalsMessageHandler::WebRTCInternalsMessageHandler() {
+  ChromeWebRTCInternals::GetInstance()->AddObserver(this);
+}
+
+WebRTCInternalsMessageHandler::~WebRTCInternalsMessageHandler() {
+  ChromeWebRTCInternals::GetInstance()->RemoveObserver(this);
+}
+
+void WebRTCInternalsMessageHandler::RegisterMessages() {
+}
+
+void WebRTCInternalsMessageHandler::OnUpdate(const std::string& command,
+                                            const base::Value* args) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  std::vector<const Value*> args_vector;
+  args_vector.push_back(args);
+  string16 update = content::WebUI::GetJavascriptCall(command, args_vector);
+
+  // Don't try to execute JavaScript in a RenderView that no longer exists.

[jam, 2013/01/18 18:27:33]

nit: this comment is just explainging what the code does, and is against the
style guide

[jiayl, 2013/01/18 19:20:00]

Done.

+  content::RenderViewHost* host =
+      web_ui()->GetWebContents()->GetRenderViewHost();
+  if (host)
+    host->ExecuteJavascriptInWebFrame(string16(), update);
+}