Gets Bubble to work on aura.

ui/gfx/compositor/layer.cc

Index: ui/gfx/compositor/layer.cc
diff --git a/ui/gfx/compositor/layer.cc b/ui/gfx/compositor/layer.cc
index e9a9ed578dfdfde1fab4b94b0af6d50f9d396cec..64b77f61ba5182317be7c808538021399ba684e2 100644
--- a/ui/gfx/compositor/layer.cc
+++ b/ui/gfx/compositor/layer.cc
@@ -614,12 +614,15 @@ void Layer::SetTransformImmediately(const ui::Transform& transform) {
 }
 
 void Layer::SetOpacityImmediately(float opacity) {
+  bool schedule_draw = (opacity != opacity_ && IsDrawn());
   opacity_ = opacity;
   SetNeedsToRecomputeHole();
 #if defined(USE_WEBKIT_COMPOSITOR)
   if (visible_)
     web_layer_.setOpacity(opacity);
 #endif
+  if (schedule_draw)
+    ScheduleDraw();
 }
 
 void Layer::SetBoundsFromAnimation(const gfx::Rect& bounds) {