mash shelf: Don't create shelf DimmerView in ShelfWidget on mus

ash/aura/wm_shelf_aura.cc

 // Copyright 2016 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/aura/wm_shelf_aura.h"
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/shelf/wm_shelf_observer.h"
 #include "ash/common/wm_window.h"
+#include "ash/shelf/dimmer_view.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shell.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 
 // WmShelfAura::AutoHideEventHandler -------------------------------------------
 
 // Forwards mouse and gesture events to ShelfLayoutManager for auto-hide.
@@ skipping 93 matching lines @@
 }
 
 void WmShelfAura::UpdateAutoHideState() {
   shelf_layout_manager_->UpdateAutoHideState();
 }
 
 ShelfBackgroundType WmShelfAura::GetBackgroundType() const {
   return shelf_layout_manager_->shelf_widget()->GetBackgroundType();
 }
 
+WmDimmerView* WmShelfAura::CreateDimmerView(bool disable_animations_for_test) {
+  return DimmerView::Create(this, disable_animations_for_test);
+}
+
 bool WmShelfAura::IsDimmed() const {
   return shelf_layout_manager_->shelf_widget()->GetDimsShelf();
 }
 
 bool WmShelfAura::IsShowingOverflowBubble() const {
   return shelf_->IsShowingOverflowBubble();
 }
 
 void WmShelfAura::SchedulePaint() {
   // Can be called during shutdown if the overflow bubble is visible.
@@ skipping 87 matching lines @@
 void WmShelfAura::OnAutoHideStateChanged(ShelfAutoHideState new_state) {
   FOR_EACH_OBSERVER(WmShelfObserver, observers_,
                     OnAutoHideStateChanged(new_state));
 }
 
 void WmShelfAura::OnShelfIconPositionsChanged() {
   FOR_EACH_OBSERVER(WmShelfObserver, observers_, OnShelfIconPositionsChanged());
 }
 
 }  // namespace ash