Web Audio: record autoplay status when an AudioContext is destroyed.

third_party/WebKit/Source/modules/webaudio/BaseAudioContext.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 89 matching lines @@
       m_closedContextSampleRate(-1),
       m_periodicWaveSine(nullptr),
       m_periodicWaveSquare(nullptr),
       m_periodicWaveSawtooth(nullptr),
       m_periodicWaveTriangle(nullptr) {
   // If mediaPlaybackRequiresUserGesture is enabled, cross origin iframes will
   // require user gesture for the AudioContext to produce sound.
   if (document->settings() &&
       document->settings()->mediaPlaybackRequiresUserGesture() &&
       document->frame() && document->frame()->isCrossOriginSubframe()) {
+    m_autoplayStatus = AutoplayStatus::AutoplayStatusFailed;
     m_userGestureRequired = true;
   }
 
   m_destinationNode = DefaultAudioDestinationNode::create(this);
 
   initialize();
 }
 
 // Constructor for offline (non-realtime) rendering.
 BaseAudioContext::BaseAudioContext(Document* document,
@@ skipping 17 matching lines @@
 
 BaseAudioContext::~BaseAudioContext() {
   deferredTaskHandler().contextWillBeDestroyed();
   // AudioNodes keep a reference to their context, so there should be no way to
   // be in the destructor if there are still AudioNodes around.
   DCHECK(!isDestinationInitialized());
   DCHECK(!m_activeSourceNodes.size());
   DCHECK(!m_finishedSourceHandlers.size());
   DCHECK(!m_isResolvingResumePromises);
   DCHECK(!m_resumeResolvers.size());
+
+  recordAutoplayStatus();

[Raymond Toy, 2016/10/10 17:05:10]

I think if the user closes a tab, everything goes away, without necessarily
calling the destructor.  Is that ok for recording the status?

[mlamouri (slow - plz ping), 2016/10/10 18:44:40]

I guess if the object is marked as GCFinalized, it should call the dtor. At
least according to the doc. I wonder if there are downsides with this or if
recording in contextDestroyed would work most of the time.

+haraken@ to give some guidance.

 }
 
 void BaseAudioContext::initialize() {
   if (isDestinationInitialized())
     return;
 
   FFTFrame::initialize();
 
   if (m_destinationNode) {
     m_destinationNode->handler().initialize();
@@ skipping 32 matching lines @@
   m_listener->waitForHRTFDatabaseLoaderThreadCompletion();
 
   clear();
 }
 
 void BaseAudioContext::contextDestroyed() {
   uninitialize();
 }
 
 bool BaseAudioContext::hasPendingActivity() const {
+  LOG(INFO) << "hasPendingActivity() => " << !m_isCleared;

[Raymond Toy, 2016/10/10 17:05:10]

Do you really want this log?  Just asking.

[mlamouri (slow - plz ping), 2016/10/10 18:44:40]

No :)

   // There's no pending activity if the audio context has been cleared.
   return !m_isCleared;
 }
 
 AudioDestinationNode* BaseAudioContext::destination() const {
   // Cannot be called from the audio thread because this method touches objects
   // managed by Oilpan, and the audio thread is not managed by Oilpan.
   DCHECK(!isAudioThread());
   return m_destinationNode;
 }
@@ skipping 337 matching lines @@
       // Initialize the table if necessary
       if (!m_periodicWaveTriangle)
         m_periodicWaveTriangle = PeriodicWave::createTriangle(sampleRate());
       return m_periodicWaveTriangle;
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
+void BaseAudioContext::maybeRecordStartAttempt() {
+  if (!m_userGestureRequired || !UserGestureIndicator::processingUserGesture())
+    return;
+
+  DCHECK(!m_autoplayStatus.has_value() ||
+         m_autoplayStatus != AutoplayStatus::AutoplayStatusSucceeded);
+  m_autoplayStatus = AutoplayStatus::AutoplayStatusFailedWithStart;
+}
+
 String BaseAudioContext::state() const {
   // These strings had better match the strings for AudioContextState in
   // AudioContext.idl.
   switch (m_contextState) {
     case Suspended:
       return "suspended";
     case Running:
       return "running";
     case Closed:
       return "closed";
@@ skipping 202 matching lines @@
   for (auto& resolver : m_decodeAudioResolvers)
     resolver->reject(
         DOMException::create(InvalidStateError, "Audio context is going away"));
   m_decodeAudioResolvers.clear();
 }
 
 void BaseAudioContext::maybeUnlockUserGesture() {
   if (!m_userGestureRequired || !UserGestureIndicator::processingUserGesture())
     return;
 
+  DCHECK(!m_autoplayStatus.has_value() ||
+         m_autoplayStatus != AutoplayStatus::AutoplayStatusSucceeded);
+
   UserGestureIndicator::utilizeUserGesture();
   m_userGestureRequired = false;
+  m_autoplayStatus = AutoplayStatus::AutoplayStatusSucceeded;
 }
 
 bool BaseAudioContext::isAllowedToStart() const {
   if (!m_userGestureRequired)
     return true;
 
   toDocument(getExecutionContext())
       ->addConsoleMessage(ConsoleMessage::create(
           JSMessageSource, WarningMessageLevel,
           "An AudioContext in a cross origin iframe must be created or resumed "
@@ skipping 10 matching lines @@
   for (auto& resolver : m_resumeResolvers) {
     resolver->reject(
         DOMException::create(InvalidStateError, "Audio context is going away"));
   }
   m_resumeResolvers.clear();
   m_isResolvingResumePromises = false;
 
   rejectPendingDecodeAudioDataResolvers();
 }
 
+void BaseAudioContext::recordAutoplayStatus() {
+  if (!m_autoplayStatus.has_value())
+    return;
+
+  DEFINE_STATIC_LOCAL(
+      EnumerationHistogram, autoplayHistogram,
+      ("WebAudio.Autoplay.CrossOrigin", AutoplayStatus::AutoplayStatusCount));
+  autoplayHistogram.count(m_autoplayStatus.value());
+
+  m_autoplayStatus.reset();
+}
+
 const AtomicString& BaseAudioContext::interfaceName() const {
   return EventTargetNames::AudioContext;
 }
 
 ExecutionContext* BaseAudioContext::getExecutionContext() const {
   return ActiveDOMObject::getExecutionContext();
 }
 
 void BaseAudioContext::startRendering() {
   // This is called for both online and offline contexts.
@@ skipping 23 matching lines @@
 }
 
 SecurityOrigin* BaseAudioContext::getSecurityOrigin() const {
   if (getExecutionContext())
     return getExecutionContext()->getSecurityOrigin();
 
   return nullptr;
 }
 
 }  // namespace blink