Continue to process AnalyserNode if inputs are silent.

third_party/WebKit/Source/modules/webaudio/AudioNode.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 411 matching lines @@
     // connected.  But internally our outputs should be disabled from the inputs
     // they're connected to.  disable() can recursively deref connections (and
     // call disable()) down a whole chain of connected nodes.
 
     // TODO(rtoy,hongchan): we need special cases the convolver, delay, biquad,
     // and IIR since they have a significant tail-time and shouldn't be
     // disconnected simply because they no longer have any input connections.
     // This needs to be handled more generally where AudioNodes have a tailTime
     // attribute. Then the AudioNode only needs to remain "active" for tailTime
     // seconds after there are no longer any active connections.
+    //
+    // The analyser node also requires special handling because we
+    // need the internal state to be updated for the time and FFT data
+    // even if it has no connections.
     if (getNodeType() != NodeTypeConvolver && getNodeType() != NodeTypeDelay &&
         getNodeType() != NodeTypeBiquadFilter &&
-        getNodeType() != NodeTypeIIRFilter) {
+        getNodeType() != NodeTypeIIRFilter &&
+        getNodeType() != NodeTypeAnalyser) {
       m_isDisabled = true;
       clearInternalStateWhenDisabled();
       for (auto& output : m_outputs)
         output->disable();
     }
   }
 }
 
 void AudioHandler::makeConnection() {
   atomicIncrement(&m_connectionRefCount);
@@ skipping 502 matching lines @@
 }
 
 void AudioNode::didAddOutput(unsigned numberOfOutputs) {
   m_connectedNodes.push_back(nullptr);
   DCHECK_EQ(numberOfOutputs, m_connectedNodes.size());
   m_connectedParams.push_back(nullptr);
   DCHECK_EQ(numberOfOutputs, m_connectedParams.size());
 }
 
 }  // namespace blink