Fix crash in VideoRendererBase::ThreadMain().

media/filters/video_renderer_base.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/video_renderer_base.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/message_loop.h"
@@ skipping 27 matching lines @@
       drop_frames_(drop_frames),
       playback_rate_(0),
       paint_cb_(paint_cb),
       set_opaque_cb_(set_opaque_cb),
       last_timestamp_(kNoTimestamp()) {
   DCHECK(!paint_cb_.is_null());
 }
 
 VideoRendererBase::~VideoRendererBase() {
   base::AutoLock auto_lock(lock_);
-  CHECK(state_ == kUninitialized || state_ == kStopped) << state_;
+  CHECK(state_ == kStopped || state_ == kUninitialized) << state_;
   CHECK_EQ(thread_, base::kNullThreadHandle);
 }
 
 void VideoRendererBase::Play(const base::Closure& callback) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   base::AutoLock auto_lock(lock_);
   DCHECK_EQ(kPrerolled, state_);
   state_ = kPlaying;
   callback.Run();
 }
@@ skipping 60 matching lines @@
     base::AutoUnlock auto_unlock(lock_);
     base::PlatformThread::Join(thread_to_join);
   }
 
   if (decrypting_demuxer_stream_) {
     decrypting_demuxer_stream_->Reset(base::Bind(
         &VideoRendererBase::StopDecoder, weak_this_, callback));
     return;
   }
 
-  decoder_->Stop(callback);
+  if (decoder_) {
+    decoder_->Stop(callback);
+    return;
+  }
+
+  callback.Run();
 }
 
 void VideoRendererBase::StopDecoder(const base::Closure& callback) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   base::AutoLock auto_lock(lock_);
   decoder_->Stop(callback);
 }
 
 void VideoRendererBase::SetPlaybackRate(float playback_rate) {
   DCHECK(message_loop_->BelongsToCurrentThread());
@@ skipping 42 matching lines @@
 
   weak_this_ = weak_factory_.GetWeakPtr();
   init_cb_ = init_cb;
   statistics_cb_ = statistics_cb;
   max_time_cb_ = max_time_cb;
   size_changed_cb_ = size_changed_cb;
   ended_cb_ = ended_cb;
   error_cb_ = error_cb;
   get_time_cb_ = get_time_cb;
   get_duration_cb_ = get_duration_cb;
+  state_ = kInitializing;
 
   scoped_ptr<VideoDecoderSelector> decoder_selector(
       new VideoDecoderSelector(base::MessageLoopProxy::current(),
                                decoders,
                                set_decryptor_ready_cb_));
 
   // To avoid calling |decoder_selector| methods and passing ownership of
   // |decoder_selector| in the same line.
   VideoDecoderSelector* decoder_selector_ptr = decoder_selector.get();
 
   decoder_selector_ptr->SelectVideoDecoder(
       stream,
       statistics_cb,
       base::Bind(&VideoRendererBase::OnDecoderSelected, weak_this_,
                  base::Passed(&decoder_selector)));
 }
 
 void VideoRendererBase::OnDecoderSelected(
     scoped_ptr<VideoDecoderSelector> decoder_selector,
     const scoped_refptr<VideoDecoder>& selected_decoder,
     const scoped_refptr<DecryptingDemuxerStream>& decrypting_demuxer_stream) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   base::AutoLock auto_lock(lock_);
 
   if (state_ == kStopped)
     return;
 
+  DCHECK_EQ(state_, kInitializing);
+
   if (!selected_decoder) {
     state_ = kUninitialized;
     base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
     return;
   }
 
   decoder_ = selected_decoder;
   decrypting_demuxer_stream_ = decrypting_demuxer_stream;
 
   // We're all good!  Consider ourselves flushed. (ThreadMain() should never
@@ skipping 279 matching lines @@
   switch (state_) {
     case kPaused:
     case kFlushing:
     case kPrerolling:
     case kPlaying:
       pending_read_ = true;
       decoder_->Read(base::Bind(&VideoRendererBase::FrameReady, weak_this_));
       return;
 
     case kUninitialized:
+    case kInitializing:
     case kPrerolled:
     case kFlushingDecoder:
     case kFlushed:
     case kEnded:
     case kStopped:
     case kError:
       return;
   }
 }
 
 void VideoRendererBase::OnDecoderResetDone() {
   base::AutoLock auto_lock(lock_);
+  if (state_ == kStopped)
+    return;
+
   DCHECK_EQ(kFlushingDecoder, state_);
   DCHECK(!pending_read_);
 
   state_ = kFlushing;
   AttemptFlush_Locked();
 }
 
 void VideoRendererBase::AttemptFlush_Locked() {
   lock_.AssertAcquired();
   DCHECK_EQ(kFlushing, state_);
@@ skipping 27 matching lines @@
   last_timestamp_ = kNoTimestamp();
   ready_frames_.clear();
 }
 
 int VideoRendererBase::NumFrames_Locked() const {
   lock_.AssertAcquired();
   return ready_frames_.size();
 }
 
 }  // namespace media