mash: Have chrome set itself as a controller interface for changing volume

chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h

Index: chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
diff --git a/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h b/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
index a1e27b94fa3694c0dd7b5744ba60a66fcc086270..095dd055f376d383f2828bd7330bedca4b242214 100644
--- a/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
+++ b/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
@@ -14,6 +14,7 @@ class ChromeLauncherControllerMus;
 class ImmersiveContextMus;
 class ImmersiveHandlerFactoryMus;
 class SystemTrayClient;
+class VolumeController;
 class VpnListForwarder;
 
 class ChromeBrowserMainExtraPartsAsh : public ChromeBrowserMainExtraParts {
@@ -31,6 +32,7 @@ class ChromeBrowserMainExtraPartsAsh : public ChromeBrowserMainExtraParts {
   std::unique_ptr<ImmersiveHandlerFactoryMus> immersive_handler_factory_;
   std::unique_ptr<ImmersiveContextMus> immersive_context_;
   std::unique_ptr<SystemTrayClient> system_tray_client_;
+  std::unique_ptr<VolumeController> volume_controller_;
   std::unique_ptr<VpnListForwarder> vpn_list_forwarder_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainExtraPartsAsh);