Continue to process AnalyserNode if inputs are silent.

third_party/WebKit/Source/modules/webaudio/AnalyserNode.cpp

Index: third_party/WebKit/Source/modules/webaudio/AnalyserNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AnalyserNode.cpp b/third_party/WebKit/Source/modules/webaudio/AnalyserNode.cpp
index 8076910c8a384269d1cd837c34308fd4035ff0f2..45f9ce26d8cbf67a051799bc48a7277a3993e518 100644
--- a/third_party/WebKit/Source/modules/webaudio/AnalyserNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AnalyserNode.cpp
@@ -50,16 +50,23 @@ AnalyserHandler::~AnalyserHandler() {
 void AnalyserHandler::process(size_t framesToProcess) {
   AudioBus* outputBus = output(0).bus();
 
-  if (!isInitialized() || !input(0).isConnected()) {
+  if (!isInitialized()) {
     outputBus->zero();
     return;
   }
 
+  // Must update the internal state even if there are no inputs.

[hongchan, 2017/02/01 01:12:11]

Not sure where this comment should be placed.

[Raymond Toy, 2017/02/01 21:23:47]

Would it help to rephrase it? Or just remove it? (But I think it's important to
say that we need to process the input because line 64 handles the case where
there are no inputs connected.)

[hongchan, 2017/02/03 18:47:40]

The comment is not really relevant to what's happening at l.59. Isn't it? That
means this will confuse us when we come back later.

[Raymond Toy, 2017/02/03 18:50:00]

How about:

// Must always update internal state with any inputs.

   AudioBus* inputBus = input(0).bus();
 
   // Give the analyser the audio which is passing through this AudioNode.
   m_analyser.writeInput(inputBus, framesToProcess);
 
+  if (!input(0).isConnected()) {
+    // No inputs, so clear the output, and propagate the silence hint.
+    outputBus->zero();
+    return;
+  }
+
   // For in-place processing, our override of pullInputs() will just pass the
   // audio data through unchanged if the channel count matches from input to
   // output (resulting in inputBus == outputBus). Otherwise, do an up-mix to