ash: Remove unnecessary WmShelf::SchedulePaint() method

ash/common/shelf/overflow_bubble.h

Index: ash/common/shelf/overflow_bubble.h
diff --git a/ash/common/shelf/overflow_bubble.h b/ash/common/shelf/overflow_bubble.h
index 1e99bbc3e75ead4739ebddac5be4a601a6bb6a9c..b806a55547eb3894e90b63cb774920e082db0fff 100644
--- a/ash/common/shelf/overflow_bubble.h
+++ b/ash/common/shelf/overflow_bubble.h
@@ -59,7 +59,9 @@ class OverflowBubble : public views::PointerWatcher,
   WmShelf* wm_shelf_;
   OverflowBubbleView* bubble_;  // Owned by views hierarchy.
   views::View* anchor_;         // Owned by ShelfView.
-  ShelfView* shelf_view_;       // Owned by |bubble_|.
+
+  // ShelfView containing the overflow items. Owned by |bubble_|.
+  ShelfView* shelf_view_;
 
   DISALLOW_COPY_AND_ASSIGN(OverflowBubble);
 };