Update web-platform-tests to revision 81962ac8802223d038b188b6f9cb88a0a9c5beee

tests/wpt/web-platform-tests/webaudio/resources/mix-testing.js

@@ -0,0 +1,23 @@
+let toneLengthSeconds = 1;
+
+// Create a buffer with multiple channels.
+// The signal frequency in each channel is the multiple of that in the first
+// channel.
+function createToneBuffer(context, frequency, duration, numberOfChannels) {
+  let sampleRate = context.sampleRate;
+  let sampleFrameLength = duration * sampleRate;
+
+  let audioBuffer =
+      context.createBuffer(numberOfChannels, sampleFrameLength, sampleRate);
+
+  let n = audioBuffer.length;
+
+  for (let k = 0; k < numberOfChannels; ++k) {
+    let data = audioBuffer.getChannelData(k);
+
+    for (let i = 0; i < n; ++i)
+      data[i] = Math.sin(frequency * (k + 1) * 2.0 * Math.PI * i / sampleRate);
+  }
+
+  return audioBuffer;
+}