AudioRenderer/Clock: Remove speculative CHECKs

Crash is gone. Only the AudioClock CHECK seems to have been hit, but
that disappeared after M62 when we stopped shipping x86 on mac.

BUG=674856

Change-Id: I446f05ae659f0fa6622b5662f9f8e7ccd206c23f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894244
Auto-Submit: Chrome Cunningham <chcunningham@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711760}

media/filters/audio_clock.cc

@@ -51,13 +51,6 @@ void AudioClock::WroteAudio(int frames_written,
   PushBufferedAudioData(frames_requested - frames_written, 0.0);
   PopBufferedAudioData(frames_played);
 
-  // Trying to track down AudioClock crash, http://crbug.com/674856.
-  // It may be that we crash due to running out of memory. |buffered_| should
-  // never come close to 1000 elements in size. In most cases it should have
-  // just one entry, though additional entries are added when playback rate
-  // changes.
-  CHECK_LT(buffered_.size(), 1000U);
-
   // Update our front and back timestamps.  The back timestamp is considered the
   // authoritative source of truth, so base the front timestamp on range of data
   // buffered.  Doing so avoids accumulation errors on the front timestamp.

media/renderers/audio_renderer_impl.cc

@@ -97,12 +97,6 @@ AudioRendererImpl::~AudioRendererImpl() {
   // 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_)
     FinishInitialization(PIPELINE_ERROR_ABORT);
 }
@@ -354,18 +348,6 @@ void AudioRendererImpl::Initialize(DemuxerStream* stream,
   DCHECK(sink_.get());
   TRACE_EVENT_ASYNC_BEGIN0("media", "AudioRendererImpl::Initialize", this);
 
-  // Trying to track down AudioClock crash, http://crbug.com/674856.
-  // Initialize should never be called while Rendering is ongoing. This can lead
-  // to race conditions between media/audio-device threads.
-  CHECK(!sink_playing_);
-  // This lock is not required by Initialize, but failing to acquire the lock
-  // would indicate a race with the rendering thread, which should not be active
-  // at this time. This is just extra verification on the |sink_playing_| CHECK
-  // above. We hold |lock_| while setting |sink_playing_|, but release the lock
-  // when calling sink_->Pause() to avoid deadlocking with the AudioMixer.
-  CHECK(lock_.Try());
-  lock_.Release();
-
   // If we are re-initializing playback (e.g. switching media tracks), stop the
   // sink first.
   if (state_ == kFlushed)