Handle disabled outputs better when enabling.

third_party/WebKit/Source/modules/webaudio/AudioNodeInput.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 76 matching lines @@
   m_disabledOutputs.add(&output);
   m_outputs.remove(&output);
   changedOutputs();
 
   // Propagate disabled state to outputs.
   handler().disableOutputsIfNecessary();
 }
 
 void AudioNodeInput::enable(AudioNodeOutput& output) {
   ASSERT(deferredTaskHandler().isGraphOwner());
-  DCHECK(m_disabledOutputs.contains(&output));
 
   // Move output from disabled list to active list.
   m_outputs.add(&output);
-  m_disabledOutputs.remove(&output);
+  if (m_disabledOutputs.size() > 0) {
+    DCHECK(m_disabledOutputs.contains(&output));
+    m_disabledOutputs.remove(&output);
+  }
   changedOutputs();
 
   // Propagate enabled state to outputs.
   handler().enableOutputsIfNecessary();
 }
 
 void AudioNodeInput::didUpdate() {
   handler().checkNumberOfChannelsForInput(this);
 }
 
@@ skipping 102 matching lines @@
     return internalSummingBus;
   }
 
   // Handle multiple connections case.
   sumAllConnections(internalSummingBus, framesToProcess);
 
   return internalSummingBus;
 }
 
 }  // namespace blink