Pass delay and timestamp to AudioSourceCallback::OnMoreData.

media/audio/mac/audio_auhal_mac.cc

Index: media/audio/mac/audio_auhal_mac.cc
diff --git a/media/audio/mac/audio_auhal_mac.cc b/media/audio/mac/audio_auhal_mac.cc
index c9134023924e8b74ecffd7346b304d0dccd64f96..bc1cff8d2dcc044dbc93df36b384b3330c2b0f58 100644
--- a/media/audio/mac/audio_auhal_mac.cc
+++ b/media/audio/mac/audio_auhal_mac.cc
@@ -6,13 +6,14 @@
 
 #include <CoreServices/CoreServices.h>
 
+#include <string>
+
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/mac/mac_logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
-#include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/base/audio_pull_fifo.h"
@@ -236,10 +237,7 @@ OSStatus AUHALStream::Render(
   // Make |output_bus_| wrap the output AudioBufferList.
   WrapBufferList(data, output_bus_.get(), number_of_frames);
 
-  // Update the playout latency.
-  const double playout_latency_frames = GetPlayoutLatency(output_time_stamp);
-  current_hardware_pending_bytes_ = static_cast<uint32_t>(
-      (playout_latency_frames + 0.5) * params_.GetBytesPerFrame());
+  current_target_playout_time_ = GetTargetPlayoutTime(output_time_stamp);
 
   if (audio_fifo_)
     audio_fifo_->Consume(output_bus_.get(), output_bus_->frames());
@@ -258,10 +256,13 @@ void AUHALStream::ProvideInput(int frame_delay, AudioBus* dest) {
     return;
   }
 
+  const base::TimeDelta delay = base::TimeDelta::FromMicroseconds(
+      frame_delay * base::Time::kMicrosecondsPerSecond / params_.sample_rate());
+  const base::TimeTicks target_playout_time =
+      current_target_playout_time_ + delay;
+
   // Supply the input data and render the output data.
-  source_->OnMoreData(dest, current_hardware_pending_bytes_ +
-                                frame_delay * params_.GetBytesPerFrame(),
-                      current_lost_frames_);
+  source_->OnMoreData(target_playout_time, current_lost_frames_, dest);
   dest->Scale(volume_);
   current_lost_frames_ = 0;
 }
@@ -334,7 +335,7 @@ double AUHALStream::GetHardwareLatency() {
       output_format_.mSampleRate) + device_latency_frames);
 }
 
-double AUHALStream::GetPlayoutLatency(
+base::TimeTicks AUHALStream::GetTargetPlayoutTime(
     const AudioTimeStamp* output_time_stamp) {
   // Ensure mHostTime is valid.
   if ((output_time_stamp->mFlags & kAudioTimeStampHostTimeValid) == 0)
@@ -351,10 +352,9 @@ double AUHALStream::GetPlayoutLatency(
   if (now_ns > output_time_ns)
     return 0;
 
-  double delay_frames = static_cast<double>
-      (1e-9 * (output_time_ns - now_ns) * output_format_.mSampleRate);
-
-  return (delay_frames + hardware_latency_frames_);
+  // TODO(jameswest): Find an alternative to FromInternalValue.
+  return base::TimeTicks::FromInternalValue(

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

I'd suggest adding a TimeTicks::FromMachAbsoluteTime(uint64_t
mach_absolute_ticks) method. We had to do a similar thing for Windows
(TimeTicks::FromQPCValue()) a couple years back for an analogous use case.

Note that the implementation of this new method can just re-use most of this
code (in base/time/time_mac.cc):
https://cs.chromium.org/chromium/src/base/time/time_mac.cc?rcl=0&l=44

Also, note that AudioConvertHostTimeToNanos() is just doing the conversion from
mach_absolute_time() tick units to nanoseconds. So, this and the prior ~12 lines
of code can just become:

  const base::TimeTicks playout_time =
      base::TimeTicks::FromMachAbsoluteTime(output_time_stamp->mHostTime);
  const base::TimeTicks now = base::TimeTicks::Now();

  if (now > playout_time)  // HACK
    return now;

  return playout_time;

...or, if you're feeling saucy and agree with my prior comment about the hack
being bogus, all those lines of code become just one:

  return base::TimeTicks::FromMachAbsoluteTime(output_time_stamp->mHostTime);

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

Done.

+      output_time_ns / base::Time::kNanosecondsPerMicrosecond);
 }
 
 void AUHALStream::UpdatePlayoutTimestamp(const AudioTimeStamp* timestamp) {