Update SetPaintToLayer to accept LayerType

ash/common/system/tray/tray_background_view.cc

 // 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.
 
 #include "ash/common/system/tray/tray_background_view.h"
 
 #include <algorithm>
 
 #include "ash/common/ash_constants.h"
 #include "ash/common/material_design/material_design_controller.h"
@@ skipping 284 matching lines @@
       widget_observer_(new TrayWidgetObserver(this)) {
   DCHECK(wm_shelf_);
   set_notify_enter_exit_on_child(true);
   set_ink_drop_base_color(kShelfInkDropBaseColor);
   set_ink_drop_visible_opacity(kShelfInkDropVisibleOpacity);
 
   tray_container_ = new TrayContainer(shelf_alignment_);
   SetContents(tray_container_);
   tray_event_filter_.reset(new TrayEventFilter);
 
-  SetPaintToLayer(true);
+  SetPaintToLayer();
   layer()->SetFillsBoundsOpaquely(false);
   // Start the tray items not visible, because visibility changes are animated.
   views::View::SetVisible(false);
 }
 
 TrayBackgroundView::~TrayBackgroundView() {
   if (GetWidget())
     GetWidget()->RemoveObserver(widget_observer_.get());
   StopObservingImplicitAnimations();
 }
@@ skipping 317 matching lines @@
 }
 
 gfx::Rect TrayBackgroundView::GetBackgroundBounds() const {
   gfx::Insets insets = GetBackgroundInsets();
   gfx::Rect bounds = GetLocalBounds();
   bounds.Inset(insets);
   return bounds;
 }
 
 }  // namespace ash