mash: Use ChromeLauncherControllerImpl, remove Mus subclass stub.

chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.h

Index: chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.h
diff --git a/chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.h b/chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.h
index 920c13a03d4acf45e1a32027c0445983cf65de07..d463ea09f36d63d21f302e18070f62ade381cc00 100644
--- a/chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.h
+++ b/chrome/browser/ui/ash/launcher/extension_app_window_launcher_controller.h
@@ -22,20 +22,20 @@ namespace extensions {
 class AppWindow;
 }
 
-class ChromeLauncherController;
+class ChromeLauncherControllerImpl;
 class Profile;
 class ExtensionAppWindowLauncherItemController;
 
 // AppWindowLauncherController observes the app window registry and the
 // aura window manager. It handles adding and removing launcher items from
-// ChromeLauncherController.
+// ChromeLauncherControllerImpl.
 class ExtensionAppWindowLauncherController
     : public AppWindowLauncherController,
       public extensions::AppWindowRegistry::Observer,
       public aura::WindowObserver {
  public:
   explicit ExtensionAppWindowLauncherController(
-      ChromeLauncherController* owner);
+      ChromeLauncherControllerImpl* owner);
   ~ExtensionAppWindowLauncherController() override;
 
   // AppWindowLauncherController: