Update shelf spacing in Chrome OS according to the MD specs

ash/system/status_area_widget_delegate.h

Index: ash/system/status_area_widget_delegate.h
diff --git a/ash/system/status_area_widget_delegate.h b/ash/system/status_area_widget_delegate.h
index 4dfa668787e1eede699f656389d455502461aeb9..38c284459b6aa41800d674408dd59f62ecfdd644 100644
--- a/ash/system/status_area_widget_delegate.h
+++ b/ash/system/status_area_widget_delegate.h
@@ -55,6 +55,11 @@ class ASH_EXPORT StatusAreaWidgetDelegate : public views::AccessiblePaneView,
  private:
   void UpdateWidgetSize();
 
+  // Sets a border on |child|. If |extend_border_to_edge| is true, then an extra
+  // wide border is added to extend the view's hit region to the edge of the
+  // screen.
+  void SetBorderOnChild(views::View* child, bool extend_border_to_edge);
+
   const FocusCycler* focus_cycler_for_testing_;
   ShelfAlignment alignment_;