AudioBufferSourceNode.start with optional parameters causes processor build-up

Source/modules/webaudio/AudioBufferSourceNode.cpp

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 467 matching lines @@
                 grainDuration,
                 0.0));
         return;
     }
 
     m_isDurationGiven = isDurationGiven;
     m_isGrain = true;
     m_grainOffset = grainOffset;
     m_grainDuration = grainDuration;
 
+    // The node is started. Add a reference to keep us alive so that audio
+    // will eventually get played even if Javascript should drop all references
+    // to this node. The reference will get dropped when the source has finished
+    // playing.
+    context()->notifySourceNodeStartedProcessing(node());
+
     // If |when| < currentTime, the source must start now according to the spec.
     // So just set startTime to currentTime in this case to start the source now.
     m_startTime = std::max(when, context()->currentTime());
 
     if (buffer())
         clampGrainParameters(buffer());
 
     m_playbackState = SCHEDULED_STATE;
 }
 
@@ skipping 183 matching lines @@
 }
 
 void AudioBufferSourceNode::start(double when, double grainOffset, double grainDuration, ExceptionState& exceptionState)
 {
     audioBufferSourceHandler().start(when, grainOffset, grainDuration, exceptionState);
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)