Add UMA histograms for WebAudio

third_party/WebKit/Source/modules/webaudio/PannerNode.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 13 matching lines @@
 
 #include "modules/webaudio/PannerNode.h"
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContext.h"
 #include "modules/webaudio/AbstractAudioContext.h"
 #include "modules/webaudio/AudioBufferSourceNode.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
+#include "platform/Histogram.h"
 #include "platform/audio/HRTFPanner.h"
 #include "wtf/MathExtras.h"
 
 namespace blink {
 
 static void fixNANs(double& x)
 {
     if (std::isnan(x) || std::isinf(x))
         x = 0.0;
 }
 
 PannerHandler::PannerHandler(
     AudioNode& node, float sampleRate,
     AudioParamHandler& positionX,
     AudioParamHandler& positionY,
     AudioParamHandler& positionZ,
     AudioParamHandler& orientationX,
     AudioParamHandler& orientationY,
     AudioParamHandler& orientationZ)
     : AudioHandler(NodeTypePanner, node, sampleRate)
     , m_listener(node.context()->listener())
-    , m_panningModel(Panner::PanningModelEqualPower)
     , m_distanceModel(DistanceEffect::ModelInverse)
     , m_isAzimuthElevationDirty(true)
     , m_isDistanceConeGainDirty(true)
     , m_lastGain(-1.0)
     , m_cachedAzimuth(0)
     , m_cachedElevation(0)
     , m_cachedDistanceConeGain(1.0f)
     , m_positionX(positionX)
     , m_positionY(positionY)
     , m_positionZ(positionZ)
     , m_orientationX(orientationX)
     , m_orientationY(orientationY)
     , m_orientationZ(orientationZ)
 {
     // Load the HRTF database asynchronously so we don't block the Javascript thread while creating the HRTF database.
     // The HRTF panner will return zeroes until the database is loaded.
     listener()->createAndLoadHRTFDatabaseLoader(node.context()->sampleRate());
 
     addInput();
     addOutput(2);
 
     // Node-specific default mixing rules.
     m_channelCount = 2;
     m_channelCountMode = ClampedMax;
     m_channelInterpretation = AudioBus::Speakers;
 
+    // Explicitly set the default panning model here so that the histograms
+    // include the default value.
+    setPanningModel("equalpower");
+
     initialize();
 }
 
 PassRefPtr<PannerHandler> PannerHandler::create(
     AudioNode& node, float sampleRate,
     AudioParamHandler& positionX,
     AudioParamHandler& positionY,
     AudioParamHandler& positionZ,
     AudioParamHandler& orientationX,
     AudioParamHandler& orientationY,
@@ skipping 185 matching lines @@
 void PannerHandler::setPanningModel(const String& model)
 {
     if (model == "equalpower")
         setPanningModel(Panner::PanningModelEqualPower);
     else if (model == "HRTF")
         setPanningModel(Panner::PanningModelHRTF);
 }
 
 bool PannerHandler::setPanningModel(unsigned model)
 {
+    DEFINE_STATIC_LOCAL(EnumerationHistogram, panningModelHistogram,
+        ("WebAudio.PannerNode.PanningModel", 2));
+    panningModelHistogram.count(model);

[Mark P, 2016/06/03 19:52:37]

Please put a comment in
third_party/WebKit/Source/platform/audio/Panner.h
by the definition that values are written to logs and should not be changed.

[Raymond Toy, 2016/06/09 19:17:10]

Done.

+
     switch (model) {
     case Panner::PanningModelEqualPower:
     case Panner::PanningModelHRTF:
         if (!m_panner.get() || model != m_panningModel) {
             // This synchronizes with process().
             MutexLocker processLocker(m_processLock);
             m_panner = Panner::create(model, sampleRate(), listener()->hrtfDatabaseLoader());
             m_panningModel = model;
         }
         break;
@@ skipping 475 matching lines @@
     visitor->trace(m_positionZ);
 
     visitor->trace(m_orientationX);
     visitor->trace(m_orientationY);
     visitor->trace(m_orientationZ);
 
     AudioNode::trace(visitor);
 }
 
 } // namespace blink