[Chromecast] Fix bad merge.

Change from internal repo was incorrectly merged in Ic7891995522870c7de8eb0f3975406e76b078a4e.

Bug: internal 140824908
Change-Id: Ie476be07223127cebd5e4e209797fa7c8462dbe0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1802960
Auto-Submit: Alex Leung <alexleung@google.com>
Commit-Queue: Yuchen Liu <yucliu@chromium.org>
Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696448}

chromecast/media/audio/cast_audio_output_stream.cc

@@ -434,10 +434,6 @@ void CastAudioOutputStream::CmaWrapper::OnPushBufferComplete(
 
   // Schedule next push buffer.
   const base::TimeTicks now = base::TimeTicks::Now();
-  render_buffer_size_estimate_ -= buffer_duration_;
-  render_buffer_size_estimate_ += now - last_push_complete_time_;
-  last_push_complete_time_ = now;
-
   base::TimeDelta delay;
   if (is_audio_prefetch_) {
     // For multizone-playback, we don't care about AV sync and want to pre-fetch