Add checks to track down AudioClock crash.

media/renderers/audio_renderer_impl.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/renderers/audio_renderer_impl.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <algorithm>
 #include <utility>
@@ skipping 76 matching lines @@
 AudioRendererImpl::~AudioRendererImpl() {
   DVLOG(1) << __func__;
   DCHECK(task_runner_->BelongsToCurrentThread());
   if (base::PowerMonitor::Get())
     base::PowerMonitor::Get()->RemoveObserver(this);
 
   // If Render() is in progress, this call will wait for Render() to finish.
   // After this call, the |sink_| will not call back into |this| anymore.
   sink_->Stop();
 
+  // Trying to track down AudioClock crash, http://crbug.com/674856. If the sink
+  // hasn't truly stopped above we will fail to acquire the lock. The sink must
+  // be stopped to avoid destroying the AudioClock while its still being used.
+  CHECK(lock_.Try());
+  lock_.Release();
+
   if (!init_cb_.is_null())
     base::ResetAndReturn(&init_cb_).Run(PIPELINE_ERROR_ABORT);
 }
 
 void AudioRendererImpl::StartTicking() {
   DVLOG(1) << __func__;
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   base::AutoLock auto_lock(lock_);
 
@@ skipping 223 matching lines @@
                                    const PipelineStatusCB& init_cb) {
   DVLOG(1) << __func__;
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(client);
   DCHECK(stream);
   DCHECK_EQ(stream->type(), DemuxerStream::AUDIO);
   DCHECK(!init_cb.is_null());
   DCHECK_EQ(kUninitialized, state_);
   DCHECK(sink_.get());
 
+  // Trying to track down AudioClock crash, http://crbug.com/674856.
+  // AudioRenderImpl should only be initialized once to avoid destroying
+  // AudioClock while the audio thread is still using it.
+  CHECK_EQ(audio_clock_.get(), nullptr);
+
   state_ = kInitializing;
   client_ = client;
 
   // Always post |init_cb_| because |this| could be destroyed if initialization
   // failed.
   init_cb_ = BindToCurrentLoop(init_cb);
 
   auto output_device_info = sink_->GetOutputDeviceInfo();
   const AudioParameters& hw_params = output_device_info.output_params();
   expecting_config_changes_ = stream->SupportsConfigChanges();
@@ skipping 638 matching lines @@
   // All channels with a zero mix are muted and can be ignored.
   std::vector<bool> channel_mask(audio_parameters_.channels(), false);
   for (size_t ch = 0; ch < matrix.size(); ++ch) {
     channel_mask[ch] = std::any_of(matrix[ch].begin(), matrix[ch].end(),
                                    [](float mix) { return !!mix; });
   }
   algorithm_->SetChannelMask(std::move(channel_mask));
 }
 
 }  // namespace media