media::SilentSinkSuspender should simulate |delay| and |delay_timestamp|

media/base/silent_sink_suspender.cc

Index: media/base/silent_sink_suspender.cc
diff --git a/media/base/silent_sink_suspender.cc b/media/base/silent_sink_suspender.cc
index 2f01ed9fcd990cedd797d3a04224e5285bfff27b..7c26da408f76401529f9039347567c979a59567a 100644
--- a/media/base/silent_sink_suspender.cc
+++ b/media/base/silent_sink_suspender.cc
@@ -53,8 +53,14 @@ int SilentSinkSuspender::Render(base::TimeDelta delay,
   // the audio data for a future transition out of silence.
   if (!dest) {
     DCHECK(is_using_fake_sink_);
-    DCHECK_EQ(delay, base::TimeDelta());
     DCHECK_EQ(prior_frames_skipped, 0);
+    // |delay_timestamp| contains the value cached at
+    // |fake_sink_transition_time_|
+    // so we simulate the real sink output, promoting |delay_timestamp| with
+    // |elapsedTime|.
+    base::TimeDelta elapsedTime =
+        base::TimeTicks::Now() - fake_sink_transition_time_;
+    delay_timestamp += elapsedTime;

[chcunningham, 2016/12/20 18:36:43]

Could be a little simpler.

// Same comment...
DCHECK_EQ(delay_timestamp, fake_sink_transition_time_);
delay_timestamp = base::TimeTicks::Now()

[Mikhail, 2016/12/20 21:45:50]

sorry, I made a mistake in the comment :( it caches actually
|latest_output_delay_timestamp_|

[chcunningham, 2016/12/21 07:02:54]

No worries. But the core of my comment is about removing the elapsedTime
calculation. Isn't your math equivalent to just setting delay_timestamp =
base::TimeTicks::Now()

 
     // If we have no buffers or a transition is pending, one or more extra
     // Render() calls have occurred in before TransitionSinks() can run, so we
@@ -90,6 +96,9 @@ int SilentSinkSuspender::Render(base::TimeDelta delay,
       first_silence_time_ = now;
     if (now - first_silence_time_ > silence_timeout_) {
       is_transition_pending_ = true;
+      latest_output_delay_ = delay;
+      latest_output_delay_timestamp_ = delay_timestamp;
+      fake_sink_transition_time_ = now;
       task_runner_->PostTask(
           FROM_HERE, base::Bind(sink_transition_callback_.callback(), true));
     }
@@ -124,8 +133,8 @@ void SilentSinkSuspender::TransitionSinks(bool use_fake_sink) {
     }
     fake_sink_.Start(
         base::Bind(base::IgnoreResult(&SilentSinkSuspender::Render),
-                   base::Unretained(this), base::TimeDelta(),
-                   base::TimeTicks::Now(), 0, nullptr));
+                   base::Unretained(this), latest_output_delay_,
+                   latest_output_delay_timestamp_, 0, nullptr));
   } else {
     fake_sink_.Stop();