Fix flaky k-rate-panner test

Change the testing scheme for k-rate panner to verify that the output
is piecewise constant for a constant source when the automation rate
is set to k-rate. Reduce the duration of the test as well; Just a few
render quanta is enough to verify that the output is piece-wise constant
and different from the a-rate output.

Also updated k-rate-constant-source.html to use the same doTest method
since the special case is supported.

Didn't actually figure out the underlying flakiness of the original
test.

Bug: 841856
Change-Id: I8e9807e530fc3b1452bae521a2660be3fbe104f9
Reviewed-on: https://chromium-review.googlesource.com/1076809Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568100}

third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioparam-interface/automation-rate-testing.js

@@ -2,6 +2,12 @@
 //
 // |options| describes how the testing of the AudioParam should be done:
 //
+//   sourceNodeName: name of source node to use for testing; defaults to
+//                   'OscillatorNode'.  If set to 'none', then no source node
+//                   is created for testing and it is assumed that the AudioNode
+//                   under test are sources and need to be started.
+//   verifyPieceWiseConstant: if true, verify that the k-rate output is
+//                            piecewise constant for each render quantum.
 //   nodeName:  name of the AudioNode to be tested
 //   nodeOptions:  options to be used in the AudioNode constructor
 //
@@ -42,7 +48,14 @@ function doTest(context, should, options) {
       context, {numberOfInputs: context.destination.numberOfChannels});
   merger.connect(context.destination);
 
-  let src = new OscillatorNode(context);
+  let src = null;
+
+  // Skip creating a source to drive the graph if |sourceNodeName| is 'none'.
+  // If |sourceNodeName| is given, use that, else default to OscillatorNode.
+  if (options.sourceNodeName !== 'none') {
+    src = new window[options.sourceNodeName || 'OscillatorNode'](context);
+  }
+
   let kRateNode = new window[options.nodeName](context, options.nodeOptions);
   let aRateNode = new window[options.nodeName](context, options.nodeOptions);
   let inverter = new GainNode(context, {gain: -1});
@@ -81,16 +94,30 @@ function doTest(context, should, options) {
     });
   });
 
+  // Connect the source, if specified.
+  if (src) {
+    src.connect(kRateNode);
+    src.connect(aRateNode);
+  }
+
   // The k-rate result is channel 0, and the a-rate result is channel 1.
-  src.connect(kRateNode).connect(merger, 0, 0);
-  src.connect(aRateNode).connect(merger, 0, 1);
+  kRateNode.connect(merger, 0, 0);
+  aRateNode.connect(merger, 0, 1);
 
   // Compute the difference between the a-rate and k-rate results and send
   // that to channel 2.
   kRateNode.connect(merger, 0, 2);
   aRateNode.connect(inverter).connect(merger, 0, 2);
 
-  src.start();
+  if (src) {
+    src.start();
+  } else {
+    // If there's no source, then assume the test nodes are sources and start
+    // them.
+    kRateNode.start();
+    aRateNode.start();
+  }
+
   return context.startRendering().then(renderedBuffer => {
     let kRateOutput = renderedBuffer.getChannelData(0);
     let aRateOutput = renderedBuffer.getChannelData(1);
@@ -113,5 +140,16 @@ function doTest(context, should, options) {
            options.prefix
          }: Difference between a-rate and k-rate ${options.nodeName}`)
         .notBeConstantValueOf(0);
+
+    if (options.verifyPieceWiseConstant) {
+      // Verify that the output from the k-rate parameter is step-wise
+      // constant.
+      for (let k = 0; k < kRateOutput.length; k += 128) {
+        should(
+            kRateOutput.slice(k, k + 128),
+            `${options.prefix} k-rate output [${k}: ${k + 127}]`)
+            .beConstantValueOf(kRateOutput[k]);
+      }
+    }
   });
 }

third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioparam-interface/k-rate-constant-source.html

@@ -6,6 +6,7 @@
     <script src="/resources/testharnessreport.js"></script>
     <script src="/webaudio/resources/audit-util.js"></script>
     <script src="/webaudio/resources/audit.js"></script>
+    <script src="automation-rate-testing.js"></script>
   </head>
 
   <body>
@@ -25,54 +26,22 @@
           length: testDuration * sampleRate
         });
 
-        let merger = new ChannelMergerNode(
-            context, {numberOfInputs: context.numberOfChannels});
-        merger.connect(context.destination);
-        let inverter = new GainNode(context, {gain: -1});
-        inverter.connect(merger, 0, 2);
-
-        let kRateNode = new ConstantSourceNode(context);
-        let aRateNode = new ConstantSourceNode(context);
-
-        kRateNode.connect(merger, 0, 0);
-        aRateNode.connect(merger, 0, 1);
-
-        kRateNode.connect(merger, 0, 2);
-        aRateNode.connect(inverter);
-
-        // Set the rate
-        kRateNode.offset.automationRate = 'k-rate';
-
-        // Automate the offset
-        kRateNode.offset.setValueAtTime(0, 0);
-        kRateNode.offset.linearRampToValueAtTime(10, testDuration);
-
-        aRateNode.offset.setValueAtTime(0, 0);
-        aRateNode.offset.linearRampToValueAtTime(10, testDuration);
-
-        kRateNode.start();
-        aRateNode.start();
-
-        context.startRendering()
-            .then(audioBuffer => {
-              let kRateOut = audioBuffer.getChannelData(0);
-              let aRateOut = audioBuffer.getChannelData(1);
-              let diff = audioBuffer.getChannelData(2);
-
-              // Verify that the outputs are different.
-              should(diff, 'Difference between a-rate and k-rate outputs')
-                  .notBeConstantValueOf(0);
-
-              // Verify that the constant source node output is step-wise
-              // constant.
-              for (let k = 0; k < kRateOut.length; k += 128) {
-                should(
-                    kRateOut.slice(k, k + 128),
-                    `k-rate output [${k}: ${k + 127}]`)
-                    .beConstantValueOf(kRateOut[k]);
+        doTest(context, should, {
+          sourceNodeName: 'none',
+          verifyPieceWiseConstant: true,
+          nodeName: 'ConstantSourceNode',
+          prefix: 'k-rate offset',
+          rateSettings: [{name: 'offset', value: 'k-rate'}],
+          automations: [{
+            name: 'offset',
+            methods: [
+              {name: 'setValueAtTime', options: [0, 0]}, {
+                name: 'linearRampToValueAtTime',
+                options: [10, testDuration]
               }
-            })
-            .then(() => task.done());
+            ]
+          }]
+        }).then(() => task.done());
       });
 
       audit.run();

third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioparam-interface/k-rate-panner.html

@@ -23,14 +23,14 @@
 
       [{name: 'positionX', initial: 0, final: 1000},
        {name: 'positionY', initial: 0, final: 1000},
-       {name: 'orientationX', initial: .1, final: 1000},
-       {name: 'orientationY', initial: .1, final: 1000},
-       {name: 'orientationZ', initial: .1, final: 1000},
+       {name: 'orientationX', initial: 1, final: 10},
+       {name: 'orientationY', initial: 1, final: 10},
+       {name: 'orientationZ', initial: 1, final: 10},
       ].forEach(paramProperty => {
         audit.define('Panner k-rate ' + paramProperty.name, (task, should) => {
           // Arbitrary sample rate and duration.
           let sampleRate = 8000;
-          let testDuration = 1;
+          let testDuration = 5 * 128 / sampleRate;
           let context = new OfflineAudioContext({
             numberOfChannels: 3,
             sampleRate: sampleRate,
@@ -38,6 +38,8 @@
           });
 
           doTest(context, should, {
+            sourceNodeName: 'ConstantSourceNode',
+            verifyPieceWiseConstant: true,
             nodeName: 'PannerNode',
             // Make the source directional so orientation matters, and set some
             // defaults for the position and orientation so that we're not on an
@@ -46,11 +48,11 @@
             nodeOptions: {
               distanceModel: 'inverse',
               coneOuterAngle: 360,
-              coneInnerAngle: 10,
-              positionX: 10,
-              positionY: 10,
-              positionZ: 10,
-              orientationX: 1,
+              coneInnerAngle: 0,
+              positionX: 1,
+              positionY: 1,
+              positionZ: 1,
+              orientationX: 0,
               orientationY: 1,
               orientationZ: 1
             },