ash: Resize PowerButtonController background layer.

ash/wm/power_button_controller.h

Index: ash/wm/power_button_controller.h
diff --git a/ash/wm/power_button_controller.h b/ash/wm/power_button_controller.h
index 27dd66f8cbf28db3399eec39c3501794c2562d54..40719d8bd046eb049b2306b80ccd9cf2f9e7c8d4 100644
--- a/ash/wm/power_button_controller.h
+++ b/ash/wm/power_button_controller.h
@@ -15,6 +15,7 @@
 #include "ui/aura/root_window_observer.h"
 
 namespace gfx {
+class Rect;
 class Size;
 }
 
@@ -120,6 +121,10 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
     // Returns true if |background_layer_| is non-NULL and visible.
     bool BackgroundLayerIsVisible() const;
 
+    // Returns |background_layer_|'s bounds, or an empty rect if the layer is
+    // NULL.
+    gfx::Rect GetBackgroundLayerBounds() const;
+
    private:
     PowerButtonController* controller_;  // not owned