chromeos: makes mus send keyevents to display root when nothing has focus

services/ui/ws/window_manager_state.h

Index: services/ui/ws/window_manager_state.h
diff --git a/services/ui/ws/window_manager_state.h b/services/ui/ws/window_manager_state.h
index 2c2488f08da4434bedf0d84fda9bdaaf3c202d49..891d1d872840c31ea35238485a0279b878972aa3 100644
--- a/services/ui/ws/window_manager_state.h
+++ b/services/ui/ws/window_manager_state.h
@@ -187,7 +187,11 @@ class WindowManagerState : public EventDispatcherDelegate,
 
   // Returns the ServerWindow that is the root of the WindowManager for
   // |window|. |window| corresponds to the root of a Display.
-  ServerWindow* GetWindowManagerRoot(ServerWindow* window);
+  ServerWindow* GetWindowManagerRootForDisplayRoot(ServerWindow* window);
+
+  // Returns the ServerWindow that is used as the root of the WindowTree for
+  // |display_root|.
+  ServerWindow* GetWindowManagerRoot(WindowManagerDisplayRoot* display_root);
 
   // Called from the callback supplied to WindowTree::OnAccelerator().
   void OnAcceleratorAck(