mash: Convert ash shelf overflow bubble to wm common types

ash/aura/wm_shelf_aura.cc

Index: ash/aura/wm_shelf_aura.cc
diff --git a/ash/aura/wm_shelf_aura.cc b/ash/aura/wm_shelf_aura.cc
index bacc3f2fe9f293a6ac7b8bdfad7cccc83a465786..2e7132579483d61addb54492e0759ca9285dd11d 100644
--- a/ash/aura/wm_shelf_aura.cc
+++ b/ash/aura/wm_shelf_aura.cc
@@ -92,6 +92,16 @@ bool WmShelfAura::IsDimmed() const {
   return shelf_layout_manager_->shelf_widget()->GetDimsShelf();
 }
 
+bool WmShelfAura::IsShowingOverflowBubble() const {
+  return shelf_->IsShowingOverflowBubble();
+}
+
+void WmShelfAura::SchedulePaint() {
+  // Can be called during shutdown if the overflow bubble is visible.
+  if (shelf_)
+    shelf_->SchedulePaint();
+}
+
 bool WmShelfAura::IsVisible() const {
   return shelf_->IsVisible();
 }