Split "Online" and "Offline" AudioContext processing

Source/modules/webaudio/AudioContext.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
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
- * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
- * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
+// Copyright 2015 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 "config.h"
-#if ENABLE(WEB_AUDIO)
 #include "modules/webaudio/AudioContext.h"
 
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
-#include "bindings/core/v8/ScriptState.h"
 #include "core/dom/DOMException.h"
-#include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
-#include "core/dom/ExecutionContextTask.h"
-#include "core/html/HTMLMediaElement.h"
-#include "modules/mediastream/MediaStream.h"
-#include "modules/webaudio/AnalyserNode.h"
-#include "modules/webaudio/AudioBuffer.h"
-#include "modules/webaudio/AudioBufferCallback.h"
-#include "modules/webaudio/AudioBufferSourceNode.h"
-#include "modules/webaudio/AudioListener.h"
-#include "modules/webaudio/AudioNodeInput.h"
-#include "modules/webaudio/AudioNodeOutput.h"
-#include "modules/webaudio/BiquadFilterNode.h"
-#include "modules/webaudio/ChannelMergerNode.h"
-#include "modules/webaudio/ChannelSplitterNode.h"
-#include "modules/webaudio/ConvolverNode.h"
-#include "modules/webaudio/DefaultAudioDestinationNode.h"
-#include "modules/webaudio/DelayNode.h"
-#include "modules/webaudio/DynamicsCompressorNode.h"
-#include "modules/webaudio/GainNode.h"
-#include "modules/webaudio/MediaElementAudioSourceNode.h"
-#include "modules/webaudio/MediaStreamAudioDestinationNode.h"
-#include "modules/webaudio/MediaStreamAudioSourceNode.h"
-#include "modules/webaudio/OfflineAudioCompletionEvent.h"
-#include "modules/webaudio/OfflineAudioContext.h"
-#include "modules/webaudio/OfflineAudioDestinationNode.h"
-#include "modules/webaudio/OscillatorNode.h"
-#include "modules/webaudio/PannerNode.h"
-#include "modules/webaudio/PeriodicWave.h"
-#include "modules/webaudio/ScriptProcessorNode.h"
-#include "modules/webaudio/StereoPannerNode.h"
-#include "modules/webaudio/WaveShaperNode.h"
-#include "platform/ThreadSafeFunctional.h"
-#include "public/platform/Platform.h"
-#include "wtf/text/WTFString.h"
 
 #if DEBUG_AUDIONODE_REFERENCES
 #include <stdio.h>
 #endif
 
+#if ENABLE(WEB_AUDIO)
+
 namespace blink {
 
-// Don't allow more than this number of simultaneous AudioContexts talking to hardware.
+// Don't allow more than this number of simultaneous AudioContexts
+// talking to hardware.
 const unsigned MaxHardwareContexts = 6;
-unsigned AudioContext::s_hardwareContextCount = 0;
-unsigned AudioContext::s_contextId = 0;
+static unsigned s_hardwareContextCount = 0;
+static unsigned s_contextId = 0;
 
-AudioContext* AudioContext::create(Document& document, ExceptionState& exceptionState)
+AbstractAudioContext* AudioContext::create(Document& document, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
     if (s_hardwareContextCount >= MaxHardwareContexts) {
         exceptionState.throwDOMException(
             NotSupportedError,
             ExceptionMessages::indexExceedsMaximumBound(
                 "number of hardware contexts",
                 s_hardwareContextCount,
                 MaxHardwareContexts));
         return nullptr;
     }
 
-    AudioContext* audioContext = new AudioContext(&document);
+    AudioContext* audioContext = new AudioContext(document);
     audioContext->suspendIfNeeded();
+
+    // This starts the audio thread. The destination node's
+    // provideInput() method will now be called repeatedly to render
+    // audio.  Each time provideInput() is called, a portion of the
+    // audio stream is rendered. Let's call this time period a "render
+    // quantum". NOTE: for now AudioContext does not need an explicit
+    // startRendering() call from JavaScript.  We may want to consider
+    // requiring it for symmetry with OfflineAudioContext.
+    audioContext->startRendering();
+    ++s_hardwareContextCount;
+#if DEBUG_AUDIONODE_REFERENCES
+    fprintf(stderr, "%p: AudioContext::AudioContext(): %u #%u\n",
+        audioContext, audioContext->m_contextId, s_hardwareContextCount);
+#endif
+
     return audioContext;
 }
 
-// Constructor for rendering to the audio hardware.
-AudioContext::AudioContext(Document* document)
-    : ActiveDOMObject(document)
-    , m_isStopScheduled(false)
-    , m_isCleared(false)
-    , m_isInitialized(false)
-    , m_destinationNode(nullptr)
-    , m_isResolvingResumePromises(false)
-    , m_connectionCount(0)
-    , m_didInitializeContextGraphMutex(false)
-    , m_deferredTaskHandler(DeferredTaskHandler::create())
-    , m_isOfflineContext(false)
-    , m_contextState(Suspended)
+AudioContext::AudioContext(Document& document)
+    : AbstractAudioContext(&document)
+    , m_contextId(s_contextId++)
 {
-    m_didInitializeContextGraphMutex = true;
-    m_destinationNode = DefaultAudioDestinationNode::create(this);
-
-    initialize();
-}
-
-// Constructor for offline (non-realtime) rendering.
-AudioContext::AudioContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate)
-    : ActiveDOMObject(document)
-    , m_isStopScheduled(false)
-    , m_isCleared(false)
-    , m_isInitialized(false)
-    , m_destinationNode(nullptr)
-    , m_isResolvingResumePromises(false)
-    , m_connectionCount(0)
-    , m_didInitializeContextGraphMutex(false)
-    , m_deferredTaskHandler(DeferredTaskHandler::create())
-    , m_isOfflineContext(true)
-    , m_contextState(Suspended)
-{
-    m_didInitializeContextGraphMutex = true;
-    // Create a new destination for offline rendering.
-    m_renderTarget = AudioBuffer::create(numberOfChannels, numberOfFrames, sampleRate);
-    if (m_renderTarget.get())
-        m_destinationNode = OfflineAudioDestinationNode::create(this, m_renderTarget.get());
-
-    initialize();
 }
 
 AudioContext::~AudioContext()
 {
 #if DEBUG_AUDIONODE_REFERENCES
     fprintf(stderr, "%p: AudioContext::~AudioContext(): %u\n", this, m_contextId);
 #endif
-    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.
-    ASSERT(!m_isInitialized);
-    ASSERT(!m_activeSourceNodes.size());
-    ASSERT(!m_finishedSourceHandlers.size());
-    ASSERT(!m_isResolvingResumePromises);
-    ASSERT(!m_resumeResolvers.size());
 }
 
-void AudioContext::initialize()
+DEFINE_TRACE(AudioContext)
 {
-    if (isInitialized())
-        return;
-
-    FFTFrame::initialize();
-    m_listener = AudioListener::create();
-
-    if (m_destinationNode.get()) {
-        m_destinationNode->handler().initialize();
-
-        if (!isOfflineContext()) {
-            // This starts the audio thread. The destination node's provideInput() method will now be called repeatedly to render audio.
-            // Each time provideInput() is called, a portion of the audio stream is rendered. Let's call this time period a "render quantum".
-            // NOTE: for now default AudioContext does not need an explicit startRendering() call from JavaScript.
-            // We may want to consider requiring it for symmetry with OfflineAudioContext.
-            startRendering();
-            ++s_hardwareContextCount;
-        }
-
-        m_contextId = s_contextId++;
-        m_isInitialized = true;
-#if DEBUG_AUDIONODE_REFERENCES
-        fprintf(stderr, "%p: AudioContext::AudioContext(): %u #%u\n",
-            this, m_contextId, AudioContext::s_hardwareContextCount);
-#endif
-    }
-}
-
-void AudioContext::clear()
-{
-    m_destinationNode.clear();
-    // The audio rendering thread is dead.  Nobody will schedule AudioHandler
-    // deletion.  Let's do it ourselves.
-    deferredTaskHandler().clearHandlersToBeDeleted();
-    m_isCleared = true;
-}
-
-void AudioContext::uninitialize()
-{
-    ASSERT(isMainThread());
-
-    if (!isInitialized())
-        return;
-
-    m_isInitialized = false;
-
-    // This stops the audio thread and all audio rendering.
-    if (m_destinationNode)
-        m_destinationNode->handler().uninitialize();
-
-    if (!isOfflineContext()) {
-        ASSERT(s_hardwareContextCount);
-        --s_hardwareContextCount;
-    }
-
-    // Get rid of the sources which may still be playing.
-    releaseActiveSourceNodes();
-
-    // Reject any pending resolvers before we go away.
-    rejectPendingResolvers();
-
-    // For an offline audio context, the completion event will set the state to closed.  For an
-    // online context, we need to do it here.  We only want to set the closed state once.
-    if (!isOfflineContext())
-        setContextState(Closed);
-
-    // Resolve the promise now, if any
-    if (m_closeResolver)
-        m_closeResolver->resolve();
-
-    ASSERT(m_listener);
-    m_listener->waitForHRTFDatabaseLoaderThreadCompletion();
-
-    clear();
-}
-
-void AudioContext::stop()
-{
-    // Usually ExecutionContext calls stop twice.
-    if (m_isStopScheduled)
-        return;
-    m_isStopScheduled = true;
-
-    // Don't call uninitialize() immediately here because the ExecutionContext is in the middle
-    // of dealing with all of its ActiveDOMObjects at this point. uninitialize() can de-reference other
-    // ActiveDOMObjects so let's schedule uninitialize() to be called later.
-    // FIXME: see if there's a more direct way to handle this issue.
-    Platform::current()->mainThread()->postTask(FROM_HERE, bind(&AudioContext::uninitialize, this));
-}
-
-bool AudioContext::hasPendingActivity() const
-{
-    // There's no pending activity if the audio context has been cleared.
-    return !m_isCleared;
-}
-
-void AudioContext::throwExceptionForClosedState(ExceptionState& exceptionState)
-{
-    exceptionState.throwDOMException(InvalidStateError, "AudioContext has been closed.");
-}
-
-AudioBuffer* AudioContext::createBuffer(unsigned numberOfChannels, size_t numberOfFrames, float sampleRate, ExceptionState& exceptionState)
-{
-    // It's ok to call createBuffer, even if the context is closed because the AudioBuffer doesn't
-    // really "belong" to any particular context.
-
-    return AudioBuffer::create(numberOfChannels, numberOfFrames, sampleRate, exceptionState);
-}
-
-void AudioContext::decodeAudioData(DOMArrayBuffer* audioData, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback, ExceptionState& exceptionState)
-{
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return;
-    }
-
-    if (!audioData) {
-        exceptionState.throwDOMException(
-            SyntaxError,
-            "invalid ArrayBuffer for audioData.");
-        return;
-    }
-    m_audioDecoder.decodeAsync(audioData, sampleRate(), successCallback, errorCallback);
-}
-
-AudioBufferSourceNode* AudioContext::createBufferSource(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    AudioBufferSourceNode* node = AudioBufferSourceNode::create(*this, sampleRate());
-
-    // Do not add a reference to this source node now. The reference will be added when start() is
-    // called.
-
-    return node;
-}
-
-MediaElementAudioSourceNode* AudioContext::createMediaElementSource(HTMLMediaElement* mediaElement, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    if (!mediaElement) {
-        exceptionState.throwDOMException(
-            InvalidStateError,
-            "invalid HTMLMedialElement.");
-        return nullptr;
-    }
-
-    // First check if this media element already has a source node.
-    if (mediaElement->audioSourceNode()) {
-        exceptionState.throwDOMException(
-            InvalidStateError,
-            "HTMLMediaElement already connected previously to a different MediaElementSourceNode.");
-        return nullptr;
-    }
-
-    MediaElementAudioSourceNode* node = MediaElementAudioSourceNode::create(*this, *mediaElement);
-
-    mediaElement->setAudioSourceNode(node);
-
-    notifySourceNodeStartedProcessing(node); // context keeps reference until node is disconnected
-    return node;
-}
-
-MediaStreamAudioSourceNode* AudioContext::createMediaStreamSource(MediaStream* mediaStream, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    if (!mediaStream) {
-        exceptionState.throwDOMException(
-            InvalidStateError,
-            "invalid MediaStream source");
-        return nullptr;
-    }
-
-    MediaStreamTrackVector audioTracks = mediaStream->getAudioTracks();
-    if (audioTracks.isEmpty()) {
-        exceptionState.throwDOMException(
-            InvalidStateError,
-            "MediaStream has no audio track");
-        return nullptr;
-    }
-
-    // Use the first audio track in the media stream.
-    MediaStreamTrack* audioTrack = audioTracks[0];
-    OwnPtr<AudioSourceProvider> provider = audioTrack->createWebAudioSource();
-    MediaStreamAudioSourceNode* node = MediaStreamAudioSourceNode::create(*this, *mediaStream, audioTrack, provider.release());
-
-    // FIXME: Only stereo streams are supported right now. We should be able to accept multi-channel streams.
-    node->setFormat(2, sampleRate());
-
-    notifySourceNodeStartedProcessing(node); // context keeps reference until node is disconnected
-    return node;
-}
-
-MediaStreamAudioDestinationNode* AudioContext::createMediaStreamDestination(ExceptionState& exceptionState)
-{
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    // Set number of output channels to stereo by default.
-    return MediaStreamAudioDestinationNode::create(*this, 2);
-}
-
-ScriptProcessorNode* AudioContext::createScriptProcessor(ExceptionState& exceptionState)
-{
-    // Set number of input/output channels to stereo by default.
-    return createScriptProcessor(0, 2, 2, exceptionState);
-}
-
-ScriptProcessorNode* AudioContext::createScriptProcessor(size_t bufferSize, ExceptionState& exceptionState)
-{
-    // Set number of input/output channels to stereo by default.
-    return createScriptProcessor(bufferSize, 2, 2, exceptionState);
-}
-
-ScriptProcessorNode* AudioContext::createScriptProcessor(size_t bufferSize, size_t numberOfInputChannels, ExceptionState& exceptionState)
-{
-    // Set number of output channels to stereo by default.
-    return createScriptProcessor(bufferSize, numberOfInputChannels, 2, exceptionState);
-}
-
-ScriptProcessorNode* AudioContext::createScriptProcessor(size_t bufferSize, size_t numberOfInputChannels, size_t numberOfOutputChannels, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    ScriptProcessorNode* node = ScriptProcessorNode::create(*this, sampleRate(), bufferSize, numberOfInputChannels, numberOfOutputChannels);
-
-    if (!node) {
-        if (!numberOfInputChannels && !numberOfOutputChannels) {
-            exceptionState.throwDOMException(
-                IndexSizeError,
-                "number of input channels and output channels cannot both be zero.");
-        } else if (numberOfInputChannels > AudioContext::maxNumberOfChannels()) {
-            exceptionState.throwDOMException(
-                IndexSizeError,
-                "number of input channels (" + String::number(numberOfInputChannels)
-                + ") exceeds maximum ("
-                + String::number(AudioContext::maxNumberOfChannels()) + ").");
-        } else if (numberOfOutputChannels > AudioContext::maxNumberOfChannels()) {
-            exceptionState.throwDOMException(
-                IndexSizeError,
-                "number of output channels (" + String::number(numberOfInputChannels)
-                + ") exceeds maximum ("
-                + String::number(AudioContext::maxNumberOfChannels()) + ").");
-        } else {
-            exceptionState.throwDOMException(
-                IndexSizeError,
-                "buffer size (" + String::number(bufferSize)
-                + ") must be a power of two between 256 and 16384.");
-        }
-        return nullptr;
-    }
-
-    notifySourceNodeStartedProcessing(node); // context keeps reference until we stop making javascript rendering callbacks
-    return node;
-}
-
-StereoPannerNode* AudioContext::createStereoPanner(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return StereoPannerNode::create(*this, sampleRate());
-}
-
-BiquadFilterNode* AudioContext::createBiquadFilter(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return BiquadFilterNode::create(*this, sampleRate());
-}
-
-WaveShaperNode* AudioContext::createWaveShaper(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return WaveShaperNode::create(*this);
-}
-
-PannerNode* AudioContext::createPanner(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return PannerNode::create(*this, sampleRate());
-}
-
-ConvolverNode* AudioContext::createConvolver(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return ConvolverNode::create(*this, sampleRate());
-}
-
-DynamicsCompressorNode* AudioContext::createDynamicsCompressor(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return DynamicsCompressorNode::create(*this, sampleRate());
-}
-
-AnalyserNode* AudioContext::createAnalyser(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return AnalyserNode::create(*this, sampleRate());
-}
-
-GainNode* AudioContext::createGain(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return GainNode::create(*this, sampleRate());
-}
-
-DelayNode* AudioContext::createDelay(ExceptionState& exceptionState)
-{
-    const double defaultMaxDelayTime = 1;
-    return createDelay(defaultMaxDelayTime, exceptionState);
-}
-
-DelayNode* AudioContext::createDelay(double maxDelayTime, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    return DelayNode::create(*this, sampleRate(), maxDelayTime, exceptionState);
-}
-
-ChannelSplitterNode* AudioContext::createChannelSplitter(ExceptionState& exceptionState)
-{
-    const unsigned ChannelSplitterDefaultNumberOfOutputs = 6;
-    return createChannelSplitter(ChannelSplitterDefaultNumberOfOutputs, exceptionState);
-}
-
-ChannelSplitterNode* AudioContext::createChannelSplitter(size_t numberOfOutputs, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    ChannelSplitterNode* node = ChannelSplitterNode::create(*this, sampleRate(), numberOfOutputs);
-
-    if (!node) {
-        exceptionState.throwDOMException(
-            IndexSizeError,
-            "number of outputs (" + String::number(numberOfOutputs)
-            + ") must be between 1 and "
-            + String::number(AudioContext::maxNumberOfChannels()) + ".");
-        return nullptr;
-    }
-
-    return node;
-}
-
-ChannelMergerNode* AudioContext::createChannelMerger(ExceptionState& exceptionState)
-{
-    const unsigned ChannelMergerDefaultNumberOfInputs = 6;
-    return createChannelMerger(ChannelMergerDefaultNumberOfInputs, exceptionState);
-}
-
-ChannelMergerNode* AudioContext::createChannelMerger(size_t numberOfInputs, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    ChannelMergerNode* node = ChannelMergerNode::create(*this, sampleRate(), numberOfInputs);
-
-    if (!node) {
-        exceptionState.throwDOMException(
-            IndexSizeError,
-            ExceptionMessages::indexOutsideRange<size_t>(
-                "number of inputs",
-                numberOfInputs,
-                1,
-                ExceptionMessages::InclusiveBound,
-                AudioContext::maxNumberOfChannels(),
-                ExceptionMessages::InclusiveBound));
-        return nullptr;
-    }
-
-    return node;
-}
-
-OscillatorNode* AudioContext::createOscillator(ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    OscillatorNode* node = OscillatorNode::create(*this, sampleRate());
-
-    // Do not add a reference to this source node now. The reference will be added when start() is
-    // called.
-
-    return node;
-}
-
-PeriodicWave* AudioContext::createPeriodicWave(DOMFloat32Array* real, DOMFloat32Array* imag, ExceptionState& exceptionState)
-{
-    ASSERT(isMainThread());
-
-    if (isContextClosed()) {
-        throwExceptionForClosedState(exceptionState);
-        return nullptr;
-    }
-
-    if (!real) {
-        exceptionState.throwDOMException(
-            SyntaxError,
-            "invalid real array");
-        return nullptr;
-    }
-
-    if (!imag) {
-        exceptionState.throwDOMException(
-            SyntaxError,
-            "invalid imaginary array");
-        return nullptr;
-    }
-
-    if (real->length() > PeriodicWave::kMaxPeriodicWaveArraySize) {
-        exceptionState.throwDOMException(
-            IndexSizeError,
-            ExceptionMessages::indexOutsideRange(
-                "length of the real part array",
-                real->length(),
-                1u,
-                ExceptionMessages::InclusiveBound,
-                PeriodicWave::kMaxPeriodicWaveArraySize,
-                ExceptionMessages::InclusiveBound));
-        return nullptr;
-    }
-
-    if (imag->length() > PeriodicWave::kMaxPeriodicWaveArraySize) {
-        exceptionState.throwDOMException(
-            IndexSizeError,
-            ExceptionMessages::indexOutsideRange(
-                "length of the imaginary part array",
-                imag->length(),
-                1u,
-                ExceptionMessages::InclusiveBound,
-                PeriodicWave::kMaxPeriodicWaveArraySize,
-                ExceptionMessages::InclusiveBound));
-        return nullptr;
-    }
-
-    if (real->length() != imag->length()) {
-        exceptionState.throwDOMException(
-            IndexSizeError,
-            "length of real array (" + String::number(real->length())
-            + ") and length of imaginary array (" +  String::number(imag->length())
-            + ") must match.");
-        return nullptr;
-    }
-
-    return PeriodicWave::create(sampleRate(), real, imag);
-}
-
-String AudioContext::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";
-    }
-    ASSERT_NOT_REACHED();
-    return "";
-}
-
-void AudioContext::setContextState(AudioContextState newState)
-{
-    ASSERT(isMainThread());
-
-    // Validate the transitions.  The valid transitions are Suspended->Running, Running->Suspended,
-    // and anything->Closed.
-    switch (newState) {
-    case Suspended:
-        ASSERT(m_contextState == Running);
-        break;
-    case Running:
-        ASSERT(m_contextState == Suspended);
-        break;
-    case Closed:
-        ASSERT(m_contextState != Closed);
-        break;
-    }
-
-    if (newState == m_contextState) {
-        // ASSERTs above failed; just return.
-        return;
-    }
-
-    m_contextState = newState;
-
-    // Notify context that state changed
-    if (executionContext())
-        executionContext()->postTask(FROM_HERE, createSameThreadTask(&AudioContext::notifyStateChange, this));
-}
-
-void AudioContext::notifyStateChange()
-{
-    dispatchEvent(Event::create(EventTypeNames::statechange));
+    visitor->trace(m_closeResolver);
+    AbstractAudioContext::trace(visitor);
 }
 
 ScriptPromise AudioContext::suspendContext(ScriptState* scriptState)
 {
     ASSERT(isMainThread());
     AutoLocker locker(this);
 
-    if (isOfflineContext()) {
-        return ScriptPromise::rejectWithDOMException(
-            scriptState,
-            DOMException::create(
-                InvalidAccessError,
-                "cannot suspend an OfflineAudioContext"));
-    }
-
     RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
 
-    if (m_contextState == Closed) {
+    if (contextState() == Closed) {
         resolver->reject(
             DOMException::create(InvalidStateError, "Cannot suspend a context that has been closed"));
     } else {
         // Stop rendering now.
-        if (m_destinationNode)
+        if (destination())
             stopRendering();
 
         // Since we don't have any way of knowing when the hardware actually stops, we'll just
         // resolve the promise now.
         resolver->resolve();
     }
 
     return promise;
 }
 
 ScriptPromise AudioContext::resumeContext(ScriptState* scriptState)
 {
     ASSERT(isMainThread());
-    AutoLocker locker(this);
-
-    if (isOfflineContext()) {
-        return ScriptPromise::rejectWithDOMException(
-            scriptState,
-            DOMException::create(
-                InvalidAccessError,
-                "cannot resume an OfflineAudioContext"));
-    }
 
     if (isContextClosed()) {
         return ScriptPromise::rejectWithDOMException(
             scriptState,
             DOMException::create(
                 InvalidAccessError,
                 "cannot resume a closed AudioContext"));
     }
 
     RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
 
     // Restart the destination node to pull on the audio graph.
-    if (m_destinationNode)
+    if (destination())
         startRendering();
 
     // Save the resolver which will get resolved when the destination node starts pulling on the
     // graph again.
-    m_resumeResolvers.append(resolver);
+    {
+        AutoLocker locker(this);
+        m_resumeResolvers.append(resolver);
+    }
 
     return promise;
 }
 
-void AudioContext::notifySourceNodeFinishedProcessing(AudioHandler* handler)
-{
-    ASSERT(isAudioThread());
-    m_finishedSourceHandlers.append(handler);
-}
-
-void AudioContext::releaseFinishedSourceNodes()
-{
-    ASSERT(isGraphOwner());
-    ASSERT(isAudioThread());
-    for (AudioHandler* handler : m_finishedSourceHandlers) {
-        for (unsigned i = 0; i < m_activeSourceNodes.size(); ++i) {
-            if (handler == &m_activeSourceNodes[i]->handler()) {
-                handler->breakConnection();
-                m_activeSourceNodes.remove(i);
-                break;
-            }
-        }
-    }
-
-    m_finishedSourceHandlers.clear();
-}
-
-void AudioContext::notifySourceNodeStartedProcessing(AudioNode* node)
-{
-    ASSERT(isMainThread());
-    AutoLocker locker(this);
-
-    m_activeSourceNodes.append(node);
-    node->handler().makeConnection();
-}
-
-void AudioContext::releaseActiveSourceNodes()
-{
-    ASSERT(isMainThread());
-    for (auto& sourceNode : m_activeSourceNodes)
-        sourceNode->handler().breakConnection();
-
-    m_activeSourceNodes.clear();
-}
-
-void AudioContext::handleStoppableSourceNodes()
-{
-    ASSERT(isGraphOwner());
-
-    // Find AudioBufferSourceNodes to see if we can stop playing them.
-    for (AudioNode* node : m_activeSourceNodes) {
-        if (node->handler().nodeType() == AudioHandler::NodeTypeAudioBufferSource) {
-            AudioBufferSourceNode* sourceNode = static_cast<AudioBufferSourceNode*>(node);
-            sourceNode->audioBufferSourceHandler().handleStoppableSourceNode();
-        }
-    }
-}
-
-void AudioContext::handlePreRenderTasks()
-{
-    ASSERT(isAudioThread());
-
-    // At the beginning of every render quantum, try to update the internal rendering graph state (from main thread changes).
-    // It's OK if the tryLock() fails, we'll just take slightly longer to pick up the changes.
-    if (tryLock()) {
-        deferredTaskHandler().handleDeferredTasks();
-
-        resolvePromisesForResume();
-
-        // Check to see if source nodes can be stopped because the end time has passed.
-        handleStoppableSourceNodes();
-
-        unlock();
-    }
-}
-
-void AudioContext::handlePostRenderTasks()
-{
-    ASSERT(isAudioThread());
-
-    // Must use a tryLock() here too.  Don't worry, the lock will very rarely be contended and this method is called frequently.
-    // The worst that can happen is that there will be some nodes which will take slightly longer than usual to be deleted or removed
-    // from the render graph (in which case they'll render silence).
-    if (tryLock()) {
-        // Take care of AudioNode tasks where the tryLock() failed previously.
-        deferredTaskHandler().breakConnections();
-
-        // Dynamically clean up nodes which are no longer needed.
-        releaseFinishedSourceNodes();
-
-        deferredTaskHandler().handleDeferredTasks();
-        deferredTaskHandler().requestToDeleteHandlersOnMainThread();
-
-        unlock();
-    }
-}
-
-void AudioContext::resolvePromisesForResumeOnMainThread()
-{
-    ASSERT(isMainThread());
-    AutoLocker locker(this);
-
-    for (auto& resolver : m_resumeResolvers) {
-        if (m_contextState == Closed) {
-            resolver->reject(
-                DOMException::create(InvalidStateError, "Cannot resume a context that has been closed"));
-        } else {
-            resolver->resolve();
-        }
-    }
-
-    m_resumeResolvers.clear();
-    m_isResolvingResumePromises = false;
-}
-
-void AudioContext::resolvePromisesForResume()
-{
-    // This runs inside the AudioContext's lock when handling pre-render tasks.
-    ASSERT(isAudioThread());
-    ASSERT(isGraphOwner());
-
-    // Resolve any pending promises created by resume(). Only do this if we haven't already started
-    // resolving these promises. This gets called very often and it takes some time to resolve the
-    // promises in the main thread.
-    if (!m_isResolvingResumePromises && m_resumeResolvers.size() > 0) {
-        m_isResolvingResumePromises = true;
-        Platform::current()->mainThread()->postTask(FROM_HERE, threadSafeBind(&AudioContext::resolvePromisesForResumeOnMainThread, this));
-    }
-}
-
-void AudioContext::rejectPendingResolvers()
-{
-    ASSERT(isMainThread());
-
-    // Audio context is closing down so reject any resume promises that are still pending.
-
-    for (auto& resolver : m_resumeResolvers) {
-        resolver->reject(DOMException::create(InvalidStateError, "Audio context is going away"));
-    }
-    m_resumeResolvers.clear();
-    m_isResolvingResumePromises = false;
-}
-
-const AtomicString& AudioContext::interfaceName() const
-{
-    return EventTargetNames::AudioContext;
-}
-
-ExecutionContext* AudioContext::executionContext() const
-{
-    return m_isStopScheduled ? 0 : ActiveDOMObject::executionContext();
-}
-
-void AudioContext::startRendering()
-{
-    // This is called for both online and offline contexts.
-    ASSERT(isMainThread());
-    ASSERT(m_destinationNode);
-
-    if (m_contextState == Suspended) {
-        destination()->audioDestinationHandler().startRendering();
-        setContextState(Running);
-    }
-}
-
-void AudioContext::stopRendering()
-{
-    ASSERT(isMainThread());
-    ASSERT(m_destinationNode);
-    ASSERT(!isOfflineContext());
-
-    if (m_contextState == Running) {
-        destination()->audioDestinationHandler().stopRendering();
-        setContextState(Suspended);
-        deferredTaskHandler().clearHandlersToBeDeleted();
-    }
-}
-
-void AudioContext::fireCompletionEvent()
-{
-    ASSERT(isMainThread());
-    if (!isMainThread())
-        return;
-
-    AudioBuffer* renderedBuffer = m_renderTarget.get();
-
-    // For an offline context, we set the state to closed here so that the oncomplete handler sees
-    // that the context has been closed.
-    setContextState(Closed);
-
-    ASSERT(renderedBuffer);
-    if (!renderedBuffer)
-        return;
-
-    // Avoid firing the event if the document has already gone away.
-    if (executionContext()) {
-        // Call the offline rendering completion event listener and resolve the promise too.
-        dispatchEvent(OfflineAudioCompletionEvent::create(renderedBuffer));
-        m_offlineResolver->resolve(renderedBuffer);
-    }
-}
-
-DEFINE_TRACE(AudioContext)
-{
-    visitor->trace(m_closeResolver);
-    visitor->trace(m_offlineResolver);
-    visitor->trace(m_renderTarget);
-    visitor->trace(m_destinationNode);
-    visitor->trace(m_listener);
-    // trace() can be called in AudioContext constructor, and
-    // m_contextGraphMutex might be unavailable.
-    if (m_didInitializeContextGraphMutex) {
-        AutoLocker lock(this);
-        visitor->trace(m_activeSourceNodes);
-    } else {
-        visitor->trace(m_activeSourceNodes);
-    }
-    visitor->trace(m_resumeResolvers);
-    RefCountedGarbageCollectedEventTargetWithInlineData<AudioContext>::trace(visitor);
-    ActiveDOMObject::trace(visitor);
-}
-
-SecurityOrigin* AudioContext::securityOrigin() const
-{
-    if (executionContext())
-        return executionContext()->securityOrigin();
-
-    return nullptr;
-}
-
 ScriptPromise AudioContext::closeContext(ScriptState* scriptState)
 {
-    if (isOfflineContext()) {
-        return ScriptPromise::rejectWithDOMException(
-            scriptState,
-            DOMException::create(InvalidAccessError, "cannot close an OfflineAudioContext."));
-    }
-
     if (isContextClosed()) {
         // We've already closed the context previously, but it hasn't yet been resolved, so just
         // create a new promise and reject it.
         return ScriptPromise::rejectWithDOMException(
             scriptState,
             DOMException::create(InvalidStateError,
                 "Cannot close a context that is being closed or has already been closed."));
     }
 
     m_closeResolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = m_closeResolver->promise();
 
     // Stop the audio context. This will stop the destination node from pulling audio anymore. And
     // since we have disconnected the destination from the audio graph, and thus has no references,
     // the destination node can GCed if JS has no references. stop() will also resolve the Promise
     // created here.
     stop();
 
     return promise;
 }
 
+void AudioContext::didClose()
+{
+    // This is specific to AudioContexts. OfflineAudioContexts
+    // are closed in their completion event.
+    setContextState(Closed);
+
+    ASSERT(s_hardwareContextCount);
+    --s_hardwareContextCount;
+
+    if (m_closeResolver)
+        m_closeResolver->resolve();
+}
+
+bool AudioContext::isContextClosed() const
+{
+    return m_closeResolver || AbstractAudioContext::isContextClosed();
+}
+
+void AudioContext::stopRendering()
+{
+    ASSERT(isMainThread());
+    ASSERT(destination());
+
+    if (contextState() == Running) {
+        destination()->audioDestinationHandler().stopRendering();
+        setContextState(Suspended);
+        deferredTaskHandler().clearHandlersToBeDeleted();
+    }
+}
+
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)