Rewrite scoped_ptr<T>(NULL) to use the default ctor.

media/audio/win/audio_unified_win.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/audio/win/audio_unified_win.h"
 
 #include <Functiondiscoverykeys_devpkey.h>
 
 #include "base/debug/trace_event.h"
 #ifndef NDEBUG
@@ skipping 100 matching lines @@
 WASAPIUnifiedStream::WASAPIUnifiedStream(AudioManagerWin* manager,
                                          const AudioParameters& params,
                                          const std::string& input_device_id)
     : creating_thread_id_(base::PlatformThread::CurrentId()),
       manager_(manager),
       params_(params),
       input_channels_(params.input_channels()),
       output_channels_(params.channels()),
       input_device_id_(input_device_id),
       share_mode_(CoreAudioUtil::GetShareMode()),
-      audio_io_thread_(NULL),
       opened_(false),
       volume_(1.0),
       output_buffer_size_frames_(0),
       input_buffer_size_frames_(0),
       endpoint_render_buffer_size_frames_(0),
       endpoint_capture_buffer_size_frames_(0),
       num_written_frames_(0),
       total_delay_ms_(0.0),
       total_delay_bytes_(0),
       source_(NULL),
@@ skipping 842 matching lines @@
 void WASAPIUnifiedStream::StopAndJoinThread(HRESULT err) {
   CHECK(GetCurrentThreadId() == creating_thread_id_);
   DCHECK(audio_io_thread_.get());
   SetEvent(stop_streaming_event_.Get());
   audio_io_thread_->Join();
   audio_io_thread_.reset();
   HandleError(err);
 }
 
 }  // namespace media