Add CombinedDesktopMediaList class

chrome/browser/ui/cocoa/media_picker/desktop_media_picker_bridge.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.
 
 #import "chrome/browser/ui/cocoa/media_picker/desktop_media_picker_bridge.h"
 
 DesktopMediaPickerBridge::DesktopMediaPickerBridge(
     id<DesktopMediaPickerObserver> observer)
     : observer_(observer) {
 }
 
 DesktopMediaPickerBridge::~DesktopMediaPickerBridge() {
 }
 
-void DesktopMediaPickerBridge::OnSourceAdded(int index) {
+void DesktopMediaPickerBridge::OnSourceAdded(DesktopMediaList* list,

[qiangchen, 2016/01/26 01:01:50]

According to style guide.
Comment the unused parameter variable name. For example:

DesktopMediaList* /*list*/

Do the same for the other functions in this file.

+                                             int index) {
   [observer_ sourceAddedAtIndex:index];
 }
 
-void DesktopMediaPickerBridge::OnSourceRemoved(int index) {
+void DesktopMediaPickerBridge::OnSourceRemoved(DesktopMediaList* list,
+                                               int index) {
   [observer_ sourceRemovedAtIndex:index];
 }
 
-void DesktopMediaPickerBridge::OnSourceMoved(int old_index, int new_index) {
+void DesktopMediaPickerBridge::OnSourceMoved(DesktopMediaList* list,
+                                             int old_index,
+                                             int new_index) {
   [observer_ sourceMovedFrom:old_index to:new_index];
 }
 
-void DesktopMediaPickerBridge::OnSourceNameChanged(int index) {
+void DesktopMediaPickerBridge::OnSourceNameChanged(DesktopMediaList* list,
+                                                   int index) {
   [observer_ sourceNameChangedAtIndex:index];
 }
 
-void DesktopMediaPickerBridge::OnSourceThumbnailChanged(int index) {
+void DesktopMediaPickerBridge::OnSourceThumbnailChanged(DesktopMediaList* list,
+                                                        int index) {
   [observer_ sourceThumbnailChangedAtIndex:index];
 }