Update shelf spacing in Chrome OS according to the MD specs

ash/system/tray/tray_background_view.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_SYSTEM_TRAY_TRAY_BACKGROUND_VIEW_H_
 #define ASH_SYSTEM_TRAY_TRAY_BACKGROUND_VIEW_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 134 matching lines @@
   }
   TrayContainer* tray_container() const { return tray_container_; }
   wm::ShelfAlignment shelf_alignment() const { return shelf_alignment_; }
   TrayEventFilter* tray_event_filter() { return tray_event_filter_.get(); }
 
   ShelfLayoutManager* GetShelfLayoutManager();
 
   // Updates the arrow visibility based on the launcher visibility.
   void UpdateBubbleViewArrow(views::TrayBubbleView* bubble_view);
 
+  virtual void GetHitRegionInsets(gfx::Insets& insets);

[bruthig, 2016/06/03 20:18:17]

Google style guide says: "All parameters passed by reference must be labeled
const."

In otherwords, use a pointer for output parameters.

+
  private:
   class TrayWidgetObserver;
 
   // Called from Initialize after all status area trays have been created.
   // Sets the border based on the position of the view.
   void SetTrayBorder();
 
   // ui::ImplicitAnimationObserver:
   void OnImplicitAnimationsCompleted() override;
   bool RequiresNotificationWhenAnimatorDestroyed() const override;
@@ skipping 27 matching lines @@
 
   std::unique_ptr<TrayWidgetObserver> widget_observer_;
   std::unique_ptr<TrayEventFilter> tray_event_filter_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayBackgroundView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_TRAY_BACKGROUND_VIEW_H_