[Media Router] Implement MediaRouterAction + MediaRouterUI tests.

chrome/browser/ui/webui/media_router/media_router_dialog_controller.cc

 // Copyright 2015 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_router/media_router_dialog_controller.h"
 
 #include <string>
 #include <vector>
 
 #include "chrome/browser/profiles/profile.h"
@@ skipping 82 matching lines @@
 #if defined(OS_MACOSX)
   *size = gfx::Size(330, 400);
 #else
   // size is not used because the dialog is auto-resizeable.
   *size = gfx::Size();
 #endif
 }
 
 }  // namespace
 
+// static
+MediaRouterDialogController*
+MediaRouterDialogController::GetOrCreateForWebContents(
+    WebContents* web_contents) {
+  DCHECK(web_contents);
+  // This call does nothing if the controller already exists.
+  MediaRouterDialogController::CreateForWebContents(web_contents);
+  return MediaRouterDialogController::FromWebContents(web_contents);
+}
+
 class MediaRouterDialogController::DialogWebContentsObserver
     : public content::WebContentsObserver {
  public:
   DialogWebContentsObserver(
       WebContents* web_contents,
       MediaRouterDialogController* dialog_controller)
       : content::WebContentsObserver(web_contents),
         dialog_controller_(dialog_controller) {
   }
 
@@ skipping 159 matching lines @@
       << "transition_type: " << transition_type << ", "
       << "nav_type: " << nav_type;
 
   media_router_dialog_pending_ = false;
 
   // TODO(imcheng): Initialize dialog.
 }
 
 }  // namespace media_router