Fix threading races on WebAudioSourceProviderImpl::provideInput

Source/core/html/HTMLMediaElement.cpp

Index: Source/core/html/HTMLMediaElement.cpp
diff --git a/Source/core/html/HTMLMediaElement.cpp b/Source/core/html/HTMLMediaElement.cpp
index 719d388704c908c3a68a8c9e1e54cd295fd7447a..a9b98e35e2ff94a6068766ec05b510b8ab92e4d7 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -343,6 +343,10 @@ HTMLMediaElement::~HTMLMediaElement()
     // See http://crbug.com/233654 for more details.
     m_completelyLoaded = true;
     m_player.clear();
+#if ENABLE(WEB_AUDIO)
+    if (audioSourceProvider())
+        audioSourceProvider()->setClient(0);
+#endif
 }
 
 void HTMLMediaElement::didMoveToNewDocument(Document* oldDocument)
@@ -3454,6 +3458,10 @@ void HTMLMediaElement::clearMediaPlayer(int flags)
     closeMediaSource();
 
     m_player.clear();
+#if ENABLE(WEB_AUDIO)
+    if (audioSourceProvider())
+        audioSourceProvider()->setClient(0);
+#endif
     stopPeriodicTimers();
     m_loadTimer.stop();