Update activity indicator from a light bar to a point

ash/shelf/shelf_button.h

Index: ash/shelf/shelf_button.h
diff --git a/ash/shelf/shelf_button.h b/ash/shelf/shelf_button.h
index 4a84a61a532d502bb5d7a60e0047ef4beea274a6..20da11f134bb13a6394378f638e0486d37f35e26 100644
--- a/ash/shelf/shelf_button.h
+++ b/ash/shelf/shelf_button.h
@@ -90,6 +90,9 @@ class ASH_EXPORT ShelfButton : public views::CustomButton {
   // Updates the status bar (bitmap, orientation, visibility).
   void UpdateBar();
 
+  // Paints an activity indicator on |canvas| whose |size| is specified in DIP.
+  void PaintIndicatorOnCanvas(gfx::Canvas* canvas, const gfx::Size& size);
+
   // The shelf view hosting this button.
   ShelfView* shelf_view_;