Fix a potential segfault in GpuVideoDecoder

media/filters/gpu_video_decoder.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 "media/filters/gpu_video_decoder.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 269 matching lines @@
 
   // If we don't have to wait for a surface complete initialization with a null
   // surface.
   CompleteInitialization(cdm_id, SurfaceManager::kNoSurfaceID);
 }
 
 void GpuVideoDecoder::CompleteInitialization(int cdm_id, int surface_id) {
   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
   DCHECK(!init_cb_.is_null());
 
+  // It's possible for the vda to become null if NotifyError is called.
+  if (!vda_) {
+    base::ResetAndReturn(&init_cb_).Run(false);
+    return;
+  }
+
   VideoDecodeAccelerator::Config vda_config;
   vda_config.profile = config_.profile();
   vda_config.cdm_id = cdm_id;
   vda_config.is_encrypted = config_.is_encrypted();
   vda_config.surface_id = surface_id;
   vda_config.is_deferred_initialization_allowed = true;
   vda_config.initial_expected_coded_size = config_.coded_size();
   if (!vda_->Initialize(vda_config, this)) {
     DVLOG(1) << "VDA::Initialize failed.";
     base::ResetAndReturn(&init_cb_).Run(false);
@@ skipping 517 matching lines @@
   }
   return false;
 }
 
 void GpuVideoDecoder::DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent()
     const {
   DCHECK(factories_->GetTaskRunner()->BelongsToCurrentThread());
 }
 
 }  // namespace media