Revert "Fix a ton of compiler warnings."

media/filters/null_audio_renderer.cc

 // Copyright (c) 2009 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 <cmath>
 
 #include "media/base/filter_host.h"
 #include "media/filters/null_audio_renderer.h"
 
 namespace media {
 
 // How "long" our buffer should be in terms of milliseconds.  In OnInitialize
 // we calculate the size of one second of audio data and use this number to
 // allocate a buffer to pass to FillBuffer.
 static const size_t kBufferSizeInMilliseconds = 100;
 
 NullAudioRenderer::NullAudioRenderer()
     : AudioRendererBase(),
       bytes_per_millisecond_(0),
       buffer_size_(0),
-      thread_(0),
+      thread_(NULL),
       shutdown_(false) {
 }
 
 NullAudioRenderer::~NullAudioRenderer() {
   Stop();
 }
 
 // static
 bool NullAudioRenderer::IsMediaFormatSupported(
     const MediaFormat& media_format) {
@@ skipping 50 matching lines @@
 
   // It's safe to start the thread now because it simply sleeps when playback
   // rate is 0.0f.
   return PlatformThread::Create(0, this, &thread_);
 }
 
 void NullAudioRenderer::OnStop() {
   shutdown_ = true;
   if (thread_) {
     PlatformThread::Join(thread_);
-    thread_ = 0;
+    thread_ = NULL;
   }
 }
 
 }  // namespace media