chromeos: Rename ash::WmShelf to Shelf

ash/shelf/overflow_bubble.h

Index: ash/shelf/overflow_bubble.h
diff --git a/ash/shelf/overflow_bubble.h b/ash/shelf/overflow_bubble.h
index d6afdf83bd8c7f0add3d28d547cb3355723fd0f9..2cc4124704f35ee4732d4d1e7a94adf460464f4c 100644
--- a/ash/shelf/overflow_bubble.h
+++ b/ash/shelf/overflow_bubble.h
@@ -16,16 +16,16 @@ class PointerEvent;
 namespace ash {
 class OverflowBubbleView;
 class OverflowButton;
+class Shelf;
 class ShelfView;
-class WmShelf;
 
 // OverflowBubble shows shelf items that won't fit on the main shelf in a
 // separate bubble.
 class OverflowBubble : public views::PointerWatcher,
                        public views::WidgetObserver {
  public:
-  // |wm_shelf| is the shelf that spawns the bubble.
-  explicit OverflowBubble(WmShelf* wm_shelf);
+  // |shelf| is the shelf that spawns the bubble.
+  explicit OverflowBubble(Shelf* shelf);
   ~OverflowBubble() override;
 
   // Shows an bubble pointing to |overflow_button| with |shelf_view| as its
@@ -50,7 +50,7 @@ class OverflowBubble : public views::PointerWatcher,
   // Overridden from views::WidgetObserver:
   void OnWidgetDestroying(views::Widget* widget) override;
 
-  WmShelf* wm_shelf_;
+  Shelf* shelf_;
   OverflowBubbleView* bubble_;       // Owned by views hierarchy.
   OverflowButton* overflow_button_;  // Owned by ShelfView.