Add extra crash logging for starting the sink with no frames.

Crash on the compositor thread is too late to debug effectively,
so cause crashes earlier.

BUG=485324
TEST=none
TBR=xhwang

Review URL: https://codereview.chromium.org/1145553002

Cr-Commit-Position: refs/heads/master@{#330026}

media/renderers/video_renderer_impl.cc

@@ -695,6 +695,7 @@ bool VideoRendererImpl::HaveReachedBufferingCap() {
 
 void VideoRendererImpl::StartSink() {
   DCHECK(task_runner_->BelongsToCurrentThread());
+  CHECK_GT(algorithm_->frames_queued(), 0u);
   sink_->Start(this);
   sink_started_ = true;
   was_background_rendering_ = false;