Implement tail processing for AudioNodes

third_party/WebKit/LayoutTests/webaudio/resources/note-grain-on-testing.js

 let sampleRate = 44100.0;
 
-// HRTF extra frames.  This is a magic constant currently in
-// AudioBufferSourceNode::process that always extends the
-// duration by this number of samples.  See bug 77224
-// (https://bugs.webkit.org/show_bug.cgi?id=77224).
-let extraFramesHRTF = 512;
-
 // How many grains to play.
 let numberOfTests = 100;
 
 // Duration of each grain to be played
 let duration = 0.01;
 
 // Time step between the start of each grain.  We need to add a little
-// bit of silence so we can detect grain boundaries and also account
-// for the extra frames for HRTF.
-let timeStep = duration + .005 + extraFramesHRTF / sampleRate;
+// bit of silence so we can detect grain boundaries
+let timeStep = duration + .005;
 
 // Time step between the start for each grain.
 let grainOffsetStep = 0.001;
 
 // How long to render to cover all of the grains.
 let renderTime = (numberOfTests + 1) * timeStep;
 
 let context;
 let renderedData;
 
 // Create a buffer containing the data that we want.  The function f
 // returns the desired value at sample frame k.
 function createSignalBuffer(context, f) {
   // Make sure the buffer has enough data for all of the possible
-  // grain offsets and durations.  Need to include the extra frames
-  // for HRTF.  The additional 1 is for any round-off errors.
-  let signalLength = Math.floor(
-      1 + extraFramesHRTF +
-      sampleRate * (numberOfTests * grainOffsetStep + duration));
+  // grain offsets and durations.  The additional 1 is for any
+  // round-off errors.
+  let signalLength =
+      Math.floor(1 + sampleRate * (numberOfTests * grainOffsetStep + duration));
 
   let buffer = context.createBuffer(2, signalLength, sampleRate);
   let data = buffer.getChannelData(0);
 
   for (let k = 0; k < signalLength; ++k) {
     data[k] = f(k);
   }
 
   return buffer;
 }
@@ skipping 73 matching lines @@
       startFrames.length == endFrames.length, 'Found all grain starts and ends')
       .beTrue();
 
   should(startFrames.length, 'Number of start frames').beEqualTo(numberOfTests);
   should(endFrames.length, 'Number of end frames').beEqualTo(numberOfTests);
 
   // Examine the start and stop times to see if they match our
   // expectations.
   for (let k = 0; k < startFrames.length; ++k) {
     let expectedStart = timeToSampleFrame(k * timeStep, sampleRate);
-    // The end point is the duration, plus the extra frames
-    // for HRTF.
-    let expectedEnd = extraFramesHRTF + expectedStart +
+    // The end point is the duration.
+    let expectedEnd = expectedStart +
         grainLengthInSampleFrames(k * grainOffsetStep, duration, sampleRate);
 
     if (startFrames[k] != expectedStart)
       ++errorCountStart;
     if (endFrames[k] != expectedEnd)
       ++errorCountEnd;
 
     should([startFrames[k], endFrames[k]], 'Pulse ' + k + ' boundary')
         .beEqualToArray([expectedStart, expectedEnd]);
   }
@@ skipping 15 matching lines @@
     should(endFrames.length, 'Number of grains that ended at the correct time')
         .beEqualTo(numberOfTests);
   } else {
     should(
         errorCountEnd,
         'Number of grains out of ' + numberOfTests +
             ' that ended at the wrong time')
         .beEqualTo(0);
   }
 }