More tracing for audio rendering

media/base/audio_renderer_mixer_input.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/audio_renderer_mixer_input.h"
 
 #include <cmath>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/trace_event/trace_event.h"
 #include "media/base/audio_renderer_mixer.h"
 #include "media/base/audio_renderer_mixer_pool.h"
 
 namespace media {
 
 AudioRendererMixerInput::AudioRendererMixerInput(
     AudioRendererMixerPool* mixer_pool,
     int owner_id,
     const std::string& device_id,
     const url::Origin& security_origin,
@@ skipping 147 matching lines @@
   started_ = true;
 
   if (was_playing)
     Play();
 
   callback.Run(OUTPUT_DEVICE_STATUS_OK);
 }
 
 double AudioRendererMixerInput::ProvideInput(AudioBus* audio_bus,
                                              uint32_t frames_delayed) {
+  TRACE_EVENT0("audio", "AudioRendererMixerInput::ProvideInput");
   int frames_filled = callback_->Render(audio_bus, frames_delayed, 0);
 
   // AudioConverter expects unfilled frames to be zeroed.
   if (frames_filled < audio_bus->frames()) {
     audio_bus->ZeroFramesPartial(
         frames_filled, audio_bus->frames() - frames_filled);
   }
 
   // We're reading |volume_| from the audio device thread and must avoid racing
   // with the main/media thread calls to SetVolume(). See thread safety comment
   // in the header file.
   {
     base::AutoLock auto_lock(volume_lock_);
     return frames_filled > 0 ? volume_ : 0;
   }
 }
 
 void AudioRendererMixerInput::OnRenderError() {
   callback_->OnRenderError();
 }
 
 }  // namespace media