Revert of WebAudio: Fix AudioNode leak in a case that AudioNode is not disconnected from the ...

Source/modules/webaudio/AudioContext.cpp

Index: Source/modules/webaudio/AudioContext.cpp
diff --git a/Source/modules/webaudio/AudioContext.cpp b/Source/modules/webaudio/AudioContext.cpp
index c83cd758fc603b2600c1117d77e63367f65402c7..54f7637fbe38c9998269b4929c17998691a8f5a8 100644
--- a/Source/modules/webaudio/AudioContext.cpp
+++ b/Source/modules/webaudio/AudioContext.cpp
@@ -111,8 +111,6 @@
     , m_connectionCount(0)
     , m_didInitializeContextGraphMutex(false)
     , m_audioThread(0)
-    , m_lastZombie(nullptr)
-    , m_lastRemovableZombie(nullptr)
     , m_isOfflineContext(false)
     , m_contextState(Suspended)
     , m_cachedSampleFrame(0)
@@ -135,8 +133,6 @@
     , m_connectionCount(0)
     , m_didInitializeContextGraphMutex(false)
     , m_audioThread(0)
-    , m_lastZombie(nullptr)
-    , m_lastRemovableZombie(nullptr)
     , m_isOfflineContext(true)
     , m_contextState(Suspended)
     , m_cachedSampleFrame(0)
@@ -173,7 +169,6 @@
     if (isInitialized())
         return;
 
-    ThreadState::current()->addMarkingTask(this);
     FFTFrame::initialize();
     m_listener = AudioListener::create();
 
@@ -244,12 +239,6 @@
     m_listener->waitForHRTFDatabaseLoaderThreadCompletion();
 
     clear();
-
-    ThreadState::current()->removeMarkingTask(this);
-    if (m_lastZombie)
-        ThreadState::current()->purifyZombies();
-    m_lastZombie = nullptr;
-    m_lastRemovableZombie = nullptr;
 }
 
 void AudioContext::stop()
@@ -996,8 +985,6 @@
         // Dynamically clean up nodes which are no longer needed.
         derefFinishedSourceNodes();
 
-        m_lastRemovableZombie = m_lastZombie;
-
         // Fixup the state of any dirty AudioSummingJunctions and AudioNodeOutputs.
         handleDirtyAudioSummingJunctions();
         handleDirtyAudioNodeOutputs();
@@ -1294,7 +1281,14 @@
     visitor->trace(m_renderTarget);
     visitor->trace(m_destinationNode);
     visitor->trace(m_listener);
-    visitor->trace(m_referencedNodes);
+    // trace() can be called in AudioContext constructor, and
+    // m_contextGraphMutex might be unavailable.
+    if (m_didInitializeContextGraphMutex) {
+        AutoLocker lock(this);
+        visitor->trace(m_referencedNodes);
+    } else {
+        visitor->trace(m_referencedNodes);
+    }
     visitor->trace(m_resumeResolvers);
     visitor->trace(m_suspendResolvers);
     visitor->trace(m_liveNodes);
@@ -1371,29 +1365,6 @@
     return promise;
 }
 
-void AudioContext::setLastZombie(void* object)
-{
-    ASSERT(isGraphOwner());
-    m_lastZombie = object;
-}
-
-void AudioContext::willStartMarking(ThreadState& threadState)
-{
-    lock();
-    if (!m_lastRemovableZombie)
-        return;
-    if (m_lastZombie != m_lastRemovableZombie)
-        return;
-    threadState.purifyZombies();
-    m_lastZombie = nullptr;
-    m_lastRemovableZombie = nullptr;
-}
-
-void AudioContext::didFinishMarking(ThreadState&)
-{
-    unlock();
-}
-
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)