ash: Add a NULL-check.

ash/wm/workspace/phantom_window_controller.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/wm/workspace/phantom_window_controller.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/coordinate_conversion.h"
 #include "third_party/skia/include/core/SkCanvas.h"
@@ skipping 88 matching lines @@
 }
 
 void PhantomWindowController::SetBounds(const gfx::Rect& bounds) {
   DCHECK(IsShowing());
   animation_.reset();
   bounds_ = bounds;
   phantom_widget_->SetBounds(bounds_);
 }
 
 void PhantomWindowController::Hide() {
-  phantom_widget_->Close();
+  if (phantom_widget_)
+    phantom_widget_->Close();
   phantom_widget_ = NULL;
 }
 
 bool PhantomWindowController::IsShowing() const {
   return phantom_widget_ != NULL;
 }
 
 void PhantomWindowController::AnimationProgressed(
     const ui::Animation* animation) {
   phantom_widget_->SetBounds(
@@ skipping 28 matching lines @@
   phantom_widget_->Show();
   // Fade the window in.
   ui::Layer* layer = phantom_widget_->GetNativeWindow()->layer();
   layer->SetOpacity(0);
   ui::ScopedLayerAnimationSettings scoped_setter(layer->GetAnimator());
   layer->SetOpacity(1);
 }
 
 }  // namespace internal
 }  // namespace ash