mash: Make system tray bubble close when another window is activated

components/mus/ws/focus_controller.cc

Index: components/mus/ws/focus_controller.cc
diff --git a/components/mus/ws/focus_controller.cc b/components/mus/ws/focus_controller.cc
index 6985893b814fd69b3e695d605bc1e3c5e297c64f..9a79fd7c0f6bf8124376da3442501af6292dc84f 100644
--- a/components/mus/ws/focus_controller.cc
+++ b/components/mus/ws/focus_controller.cc
@@ -75,6 +75,8 @@ void FocusController::SetFocusedWindow(ServerWindow* window) {
   if (GetFocusedWindow() == window)
     return;
 
+  // TODO(jamescook): Failures to set focus should be propagated back to the
+  // client so it doesn't get out of sync. http://crbug.com/600869
   SetFocusedWindowImpl(FocusControllerChangeSource::EXPLICIT, window);
 }