mash: Remove WorkspaceLayoutManagerDelegate.

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"
@@ skipping 126 matching lines @@
   // Can be called during shutdown if the overflow bubble is visible.
   if (shelf_)
     shelf_->SchedulePaint();
 }
 
 bool WmShelfAura::IsVisible() const {
   return shelf_->IsVisible();
 }
 
 void WmShelfAura::UpdateVisibilityState() {
-  shelf_layout_manager_->UpdateVisibilityState();
+  if (shelf_layout_manager_)
+    shelf_layout_manager_->UpdateVisibilityState();
 }
 
 ShelfVisibilityState WmShelfAura::GetVisibilityState() const {
   return shelf_layout_manager_ ? shelf_layout_manager_->visibility_state()
                                : SHELF_HIDDEN;
 }
 
 gfx::Rect WmShelfAura::GetIdealBounds() {
   return shelf_layout_manager_->GetIdealBounds();
 }
@@ skipping 67 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