Aura: New window shadows, desktop background debug toggle

ash/wm/shadow_controller.h

Index: ash/wm/shadow_controller.h
diff --git a/ash/wm/shadow_controller.h b/ash/wm/shadow_controller.h
index b1c7e7ac24df75d57850feb70c0349058287181a..ea3862de9629a6487c534f4de24e3f9dcf4230f3 100644
--- a/ash/wm/shadow_controller.h
+++ b/ash/wm/shadow_controller.h
@@ -70,6 +70,9 @@ class ASH_EXPORT ShadowController : public aura::EnvObserver,
   // exists.
   Shadow* GetShadowForWindow(aura::Window* window);
 
+  // Updates the shadow style for |window| based on whether it is |active|.
+  void HandleWindowActivationChange(aura::Window* window, bool active);
+
   // Shows or hides |window|'s shadow as needed (creating the shadow if
   // necessary).
   void HandlePossibleShadowVisibilityChange(aura::Window* window);