Properly protect state variable by locking

content/common/gpu/media/vaapi_video_decode_accelerator.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 "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 697 matching lines @@
       &VaapiVideoDecodeAccelerator::DecodeTask,
       base::Unretained(this)));
   }
 
   DVLOG(1) << "Reset finished";
 }
 
 void VaapiVideoDecodeAccelerator::Cleanup() {
   DCHECK_EQ(message_loop_, base::MessageLoop::current());
 
+  base::AutoLock auto_lock(lock_);
   if (state_ == kUninitialized || state_ == kDestroying)
     return;
 
   DVLOG(1) << "Destroying VAVDA";
-  base::AutoLock auto_lock(lock_);
   state_ = kDestroying;
 
   client_ptr_factory_.reset();
   weak_this_factory_.InvalidateWeakPtrs();
 
   // Signal all potential waiters on the decoder_thread_, let them early-exit,
   // as we've just moved to the kDestroying state, and wait for all tasks
   // to finish.
   input_ready_.Signal();
   surfaces_available_.Signal();
   {
     base::AutoUnlock auto_unlock(lock_);
     decoder_thread_.Stop();
   }
 
   state_ = kUninitialized;
 }
 
 void VaapiVideoDecodeAccelerator::Destroy() {
   DCHECK_EQ(message_loop_, base::MessageLoop::current());
   Cleanup();
   delete this;
 }
 
 bool VaapiVideoDecodeAccelerator::CanDecodeOnIOThread() {
   return false;
 }
 
 }  // namespace content