Pass delay and timestamp to AudioSourceCallback::OnMoreData.

media/audio/android/opensles_output.cc

Index: media/audio/android/opensles_output.cc
diff --git a/media/audio/android/opensles_output.cc b/media/audio/android/opensles_output.cc
index 5dc916ae03a565994736814dfee7d47ba2fc332d..9eb6795e16bb75834ff4fc4f3bbf88ee022f1a94 100644
--- a/media/audio/android/opensles_output.cc
+++ b/media/audio/android/opensles_output.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "media/audio/android/audio_manager_android.h"
 
@@ -340,16 +341,23 @@ void OpenSLESOutputStream::FillBufferQueueNoLock() {
   // Calculate the position relative to the number of frames written.
   uint32_t position_in_ms = 0;
   SLresult err = (*player_)->GetPosition(player_, &position_in_ms);
-  const int delay =
-      err == SL_RESULT_SUCCESS
-          ? -delay_calculator_.GetFramesToTarget(
-                base::TimeDelta::FromMilliseconds(position_in_ms)) *
-                bytes_per_frame_
-          : 0;
+  // Calculate the delay in frames.

[miu, 2016/08/31 23:26:54]

nit: At first glance it feels wonky to get a time position, convert it to a
frame delay, and then convert that back to a time position in the code later.
However, this is absolutely correct because one is relative to the audio
system's clock, which is different from the system reference clock (the one that
creates TimeTicks values).

So, could you elaborate on this comment here? Perhaps something like:

"Given the media time position, compute the approximate number of frames
currently queued for playout. This will be added to the system reference time
below to compute the approximate playout time of the audio to be rendered in the
call to OnMoreData() below."

[James West, 2016/09/13 07:40:50]

Done.

+  const int delay = err == SL_RESULT_SUCCESS
+                        ? -delay_calculator_.GetFramesToTarget(
+                              base::TimeDelta::FromMilliseconds(position_in_ms))
+                        : 0;
   DCHECK_GE(delay, 0);
 
+  // Calculate when the requested data will be played by converting the delay to
+  // time and adding it to the current time.
+  const base::TimeTicks target_playout_time =
+      base::TimeTicks::Now() +
+      base::TimeDelta::FromMicroseconds(
+          delay * base::Time::kMicrosecondsPerSecond / format_.samplesPerSec);
+
   // Read data from the registered client source.
-  const int frames_filled = callback_->OnMoreData(audio_bus_.get(), delay, 0);
+  const int frames_filled =
+      callback_->OnMoreData(target_playout_time, 0, audio_bus_.get());
   if (frames_filled <= 0) {
     // Audio source is shutting down, or halted on error.
     return;