Add TRACE_EVENTX() in WebAudio rendering pipe line

third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.cpp

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  */
 
 #include "modules/webaudio/AudioDestinationNode.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
 #include "modules/webaudio/BaseAudioContext.h"
 #include "platform/audio/AudioUtilities.h"
 #include "platform/audio/DenormalDisabler.h"
+#include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/wtf/Atomics.h"
 
 namespace blink {
 
 AudioDestinationHandler::AudioDestinationHandler(AudioNode& node)
     : AudioHandler(kNodeTypeDestination, node, 0), current_sample_frame_(0) {
   AddInput();
 }
 
 AudioDestinationHandler::~AudioDestinationHandler() {
   DCHECK(!IsInitialized());
 }
 
 void AudioDestinationHandler::Render(AudioBus* source_bus,
                                      AudioBus* destination_bus,
                                      size_t number_of_frames,
                                      const AudioIOPosition& output_position) {
+  TRACE_EVENT0("webaudio", "AudioDestinationHandler::Render");
+
   // We don't want denormals slowing down any of the audio processing
   // since they can very seriously hurt performance.  This will take care of all
   // AudioNodes because they all process within this scope.
   DenormalDisabler denormal_disabler;
 
   // Need to check if the context actually alive. Otherwise the subsequent
   // steps will fail. If the context is not alive somehow, return immediately
   // and do nothing.
   //
   // TODO(hongchan): because the context can go away while rendering, so this
@@ skipping 58 matching lines @@
 AudioDestinationHandler& AudioDestinationNode::GetAudioDestinationHandler()
     const {
   return static_cast<AudioDestinationHandler&>(Handler());
 }
 
 unsigned long AudioDestinationNode::maxChannelCount() const {
   return GetAudioDestinationHandler().MaxChannelCount();
 }
 
 }  // namespace blink