Check that capture_device_ is valid before setting the rotation on it

media/video/capture/linux/video_capture_device_chromeos.cc

 // Copyright 2014 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 "media/video/capture/linux/video_capture_device_chromeos.h"
 
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "ui/gfx/display.h"
@@ skipping 64 matching lines @@
   void SendDisplayRotation(const gfx::Display& display) {
     DCHECK(capture_task_runner_->BelongsToCurrentThread());
     capture_task_runner_->PostTask(
         FROM_HERE,
         base::Bind(&ScreenObserverDelegate::SendDisplayRotationOnCaptureThread,
                    this, display));
   }
 
   void SendDisplayRotationOnCaptureThread(const gfx::Display& display) {
     DCHECK(capture_task_runner_->BelongsToCurrentThread());
-    capture_device_->SetDisplayRotation(display);
+    if (capture_device_)
+      capture_device_->SetDisplayRotation(display);
   }
 
   VideoCaptureDeviceChromeOS* capture_device_;
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> capture_task_runner_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(ScreenObserverDelegate);
 };
 
 
 VideoCaptureDeviceChromeOS::VideoCaptureDeviceChromeOS(
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
     const Name& device_name)
     : VideoCaptureDeviceLinux(device_name),
       screen_observer_delegate_(new ScreenObserverDelegate(this,
                                                            ui_task_runner)) {
 }
 
 VideoCaptureDeviceChromeOS::~VideoCaptureDeviceChromeOS() {
   screen_observer_delegate_->RemoveObserver();
 }
 
 void VideoCaptureDeviceChromeOS::SetDisplayRotation(
     const gfx::Display& display) {
   if (display.IsInternal())
     SetRotation(display.rotation() * 90);
 }
 
 }  // namespace media