Remove modules/webaudio/MediaElementAudioSourceNode.h dependency from core.

Source/core/html/HTMLMediaElement.h

Index: Source/core/html/HTMLMediaElement.h
diff --git a/Source/core/html/HTMLMediaElement.h b/Source/core/html/HTMLMediaElement.h
index e1e1500d6506097b355bb2b38ecf9ca8fae054bd..9dd0c34bc1a900b0430f97636ba4d717c38caf7d 100644
--- a/Source/core/html/HTMLMediaElement.h
+++ b/Source/core/html/HTMLMediaElement.h
@@ -46,7 +46,7 @@ namespace WebCore {
 
 #if ENABLE(WEB_AUDIO)
 class AudioSourceProvider;
-class MediaElementAudioSourceNode;
+class AudioSourceProviderClient;
 #endif
 class ContentType;
 class Event;
@@ -255,8 +255,8 @@ public:
     virtual void contextDestroyed() OVERRIDE FINAL;
 
 #if ENABLE(WEB_AUDIO)
-    MediaElementAudioSourceNode* audioSourceNode() { return m_audioSourceNode; }
-    void setAudioSourceNode(MediaElementAudioSourceNode*);
+    AudioSourceProviderClient* audioSourceNode() { return m_audioSourceNode; }
+    void setAudioSourceNode(AudioSourceProviderClient*);
 
     AudioSourceProvider* audioSourceProvider();
 #endif
@@ -512,9 +512,7 @@ private:
 
 #if ENABLE(WEB_AUDIO)
     // This is a weak reference, since m_audioSourceNode holds a reference to us.
-    // The value is set just after the MediaElementAudioSourceNode is created.
-    // The value is cleared in MediaElementAudioSourceNode::~MediaElementAudioSourceNode().
-    MediaElementAudioSourceNode* m_audioSourceNode;
+    AudioSourceProviderClient* m_audioSourceNode;
 #endif
 
     friend class MediaController;