WebAudio: Remove AudioNode::RefType.

Source/modules/webaudio/AudioBufferSourceNode.h

Index: Source/modules/webaudio/AudioBufferSourceNode.h
diff --git a/Source/modules/webaudio/AudioBufferSourceNode.h b/Source/modules/webaudio/AudioBufferSourceNode.h
index cb24a38c09abeaf47b8781f3a3c48fec9ed56821..907b1e40295c939759ea2a6b2bdf35b6908eaeca 100644
--- a/Source/modules/webaudio/AudioBufferSourceNode.h
+++ b/Source/modules/webaudio/AudioBufferSourceNode.h
@@ -130,9 +130,12 @@ private:
     // It incorporates the base pitch rate, any sample-rate conversion factor from the buffer, and any doppler shift from an associated panner node.
     double totalPitchRate();
 
-    // We optionally keep track of a panner node which has a doppler shift that is incorporated into
-    // the pitch rate. We manually manage ref-counting because we want to use RefTypeConnection.
-    PannerNode* m_pannerNode;
+    // We optionally keep track of a panner node which has a doppler shift that
+    // is incorporated into the pitch rate.
+    // This RefPtr is connection reference. We must call AudioNode::
+    // makeConnection() after ref(), and call AudioNode::breakConnection()
+    // before deref().
+    RefPtr<PannerNode> m_pannerNode;
 
     // This synchronizes process() with setBuffer() which can cause dynamic channel count changes.
     mutable Mutex m_processLock;