Implement suspend() and resume() for OfflineAudioContext

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

Index: third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
index cf61288c02652c5ddea7bdd8b5ab02914b70e4f7..5659421d04b15f02ba97b0545a013562c5b1f5ea 100644
--- a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.cpp
@@ -82,8 +82,8 @@ AbstractAudioContext* AbstractAudioContext::create(Document& document, Exception
 // Constructor for rendering to the audio hardware.
 AbstractAudioContext::AbstractAudioContext(Document* document)
     : ActiveDOMObject(document)
-    , m_isCleared(false)
     , m_destinationNode(nullptr)
+    , m_isCleared(false)
     , m_isResolvingResumePromises(false)
     , m_connectionCount(0)
     , m_didInitializeContextGraphMutex(false)
@@ -99,8 +99,8 @@ AbstractAudioContext::AbstractAudioContext(Document* document)
 // Constructor for offline (non-realtime) rendering.
 AbstractAudioContext::AbstractAudioContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate)
     : ActiveDOMObject(document)
-    , m_isCleared(false)
     , m_destinationNode(nullptr)
+    , m_isCleared(false)
     , m_isResolvingResumePromises(false)
     , m_connectionCount(0)
     , m_didInitializeContextGraphMutex(false)
@@ -108,12 +108,6 @@ AbstractAudioContext::AbstractAudioContext(Document* document, unsigned numberOf
     , m_contextState(Suspended)
 {
     m_didInitializeContextGraphMutex = true;

[Raymond Toy, 2015/10/16 23:32:36]

Why is this initialized to true here and false in line 106?

(Not part of your CL. I just noticed this.)

[hongchan, 2015/10/19 20:08:12]

It has been like this from the beginning. Honestly I couldn't figure out why,
but I assumed that the mutex is false before the actual execution of constructor
and the timing might be important?

-    // 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();
 }
 
 AbstractAudioContext::~AbstractAudioContext()
@@ -804,34 +798,8 @@ void AbstractAudioContext::startRendering()
     }
 }
 
-void AbstractAudioContext::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(AbstractAudioContext)
 {
-    visitor->trace(m_offlineResolver);
-    visitor->trace(m_renderTarget);
     visitor->trace(m_destinationNode);
     visitor->trace(m_listener);
     // trace() can be called in AbstractAudioContext constructor, and