Hook up proper FocusController for simple_wm.

ui/views/window/custom_frame_view.cc

Index: ui/views/window/custom_frame_view.cc
diff --git a/ui/views/window/custom_frame_view.cc b/ui/views/window/custom_frame_view.cc
index fe392518a1e8f9f879800b8cf8d94b3c9378314f..bac98a4181af8df101cb57b90c406e25a584f47d 100644
--- a/ui/views/window/custom_frame_view.cc
+++ b/ui/views/window/custom_frame_view.cc
@@ -207,6 +207,13 @@ void CustomFrameView::SizeConstraintsChanged() {
   LayoutWindowControls();
 }
 
+void CustomFrameView::ActivationChanged(bool active) {
+  if (active_ == active)
+    return;
+  active_ = active;
+  SchedulePaint();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // CustomFrameView, View overrides: