Add NULL check before CanPauseForPendingResizeOrRepaints

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/basictypes.h"
@@ skipping 2197 matching lines @@
 
 void RenderWidgetHostViewMac::PauseForPendingResizeOrRepaintsAndDraw() {
   if (!render_widget_host_ || render_widget_host_->is_hidden())
     return;
 
   // Pausing for the overlay view prevents the underlay from receiving
   // frames. This may lead to large delays, causing overlaps. If both
   // overlay and underlay resize at the same time, let them both to have
   // some time waiting. See crbug.com/352020.
   if (underlay_view_ &&
+      underlay_view_->render_widget_host_ &&
       !underlay_view_->render_widget_host_->
           CanPauseForPendingResizeOrRepaints())
     return;
 
   // Ensure that all frames are acked before waiting for a frame to come in.
   // Note that we will draw a frame at the end of this function, so it is safe
   // to ack a never-drawn frame here.
   SendPendingSwapAck();
 
   // Wait for a frame of the right size to come in.
@@ skipping 2082 matching lines @@
 }
 
 - (void)disableRendering {
   // Disable the fade-out animation as the layer is removed.
   ScopedCAActionDisabler disabler;
   [self removeFromSuperlayer];
   renderWidgetHostView_ = nil;
 }
 
 @end  // implementation SoftwareLayer