Fix mash shelf alignment change layout regression.

ash/shelf/shelf_layout_manager.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/shelf/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <string>
@@ skipping 503 matching lines @@
   }
 }
 
 void ShelfLayoutManager::OnLockStateChanged(bool locked) {
   // Force the shelf to layout for alignment (bottom if locked, restore
   // the previous alignment otherwise).
   state_.is_screen_locked = locked;
   UpdateShelfVisibilityAfterLoginUIChange();
 }
 
+void ShelfLayoutManager::OnShelfAlignmentChanged(aura::Window* root_window) {
+  if (aura::GetMusWindow(shelf_->GetNativeWindow()))

[James Cook, 2016/05/09 19:39:36]

I think ash::Shell::GetInstance()->in_mus() would be clearer, since it doesn't
conflate the mus-check with the window-existance-check.

[msw, 2016/05/09 19:50:00]

Done.

+    LayoutShelf();
+}
+
 void ShelfLayoutManager::OnShelfAutoHideBehaviorChanged(
     aura::Window* root_window) {
   UpdateVisibilityState();
 }
 
 void ShelfLayoutManager::OnWindowActivated(
     aura::client::ActivationChangeObserver::ActivationReason reason,
     aura::Window* gained_active,
     aura::Window* lost_active) {
   UpdateAutoHideStateNow();
@@ skipping 607 matching lines @@
   UpdateBoundsAndOpacity(target_bounds, true, NULL);
   UpdateVisibilityState();
 }
 
 void ShelfLayoutManager::UpdateShelfVisibilityAfterLoginUIChange() {
   UpdateVisibilityState();
   LayoutShelf();
 }
 
 }  // namespace ash