Cleanup DesktopMediaPicker

chrome/browser/ui/cocoa/media_picker/desktop_media_picker_cocoa.mm

 // Copyright 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/cocoa/media_picker/desktop_media_picker_cocoa.h"
 
 #import "chrome/browser/ui/cocoa/media_picker/desktop_media_picker_controller.h"
 
 DesktopMediaPickerCocoa::DesktopMediaPickerCocoa() {
 }
 
 DesktopMediaPickerCocoa::~DesktopMediaPickerCocoa() {
 }
 
 void DesktopMediaPickerCocoa::Show(content::WebContents* web_contents,
-                                   gfx::NativeWindow context,
-                                   gfx::NativeWindow parent,
                                    const base::string16& app_name,
                                    const base::string16& target_name,
                                    scoped_ptr<DesktopMediaList> media_list,
                                    const DoneCallback& done_callback) {
-  controller_.reset(
-      [[DesktopMediaPickerController alloc] initWithMediaList:media_list.Pass()
-                                                       parent:parent
-                                                     callback:done_callback
-                                                      appName:app_name
-                                                   targetName:target_name]);
+  controller_.reset([[DesktopMediaPickerController alloc]
+      initWithMediaList:media_list.Pass()
+                 parent:web_contents->GetTopLevelNativeWindow()
+               callback:done_callback
+                appName:app_name
+             targetName:target_name]);
   [controller_ showWindow:nil];
 }
 
 // static
 scoped_ptr<DesktopMediaPicker> DesktopMediaPicker::Create() {
   return scoped_ptr<DesktopMediaPicker>(new DesktopMediaPickerCocoa());
 }