Fix WebAudio WPT tests that timeout.

- AudioParam IDL test:
  Actually add the IDL to the test.  Also removed unused helpers.js.
- MediaElementAudioSourceNode
  Fix error because the expected result is mono, so only has one channel.
  However, this still fails on bots because there's no audio hardware to
  drive the online context.

Bug: 626703
Test: the-audioparam-interface/idl-test.html
Change-Id: I987ad1219da1b6b6ef677f2923416634fa281d5f
Reviewed-on: https://chromium-review.googlesource.com/920261
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537856}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1903,9 +1903,8 @@ crbug.com/626703 external/wpt/wasm/wasm_local_iframe_test.html [ Failure ]
 crbug.com/626703 external/wpt/wasm/wasm_serialization_tests.html [ Failure ]
 crbug.com/626703 external/wpt/wasm/wasm_service_worker_test.https.html [ Failure ]
 crbug.com/626703 external/wpt/web-animations/animation-model/animation-types/accumulation-per-property.html [ Timeout ]
-crbug.com/626703 external/wpt/webaudio/the-audio-api/the-audioparam-interface/idl-test.html [ Timeout ]
-crbug.com/812301 external/wpt/webaudio/the-audio-api/the-audioparam-interface/retrospective-exponentialRampToValueAtTime.html [ Failure ]
-crbug.com/812301 external/wpt/webaudio/the-audio-api/the-audioparam-interface/retrospective-linearRampToValueAtTime.html [ Failure ]
+crbug.com/626703 external/wpt/webaudio/the-audio-api/the-audioparam-interface/retrospective-exponentialRampToValueAtTime.html [ Failure ]
+crbug.com/626703 external/wpt/webaudio/the-audio-api/the-audioparam-interface/retrospective-linearRampToValueAtTime.html [ Failure ]
 crbug.com/626703 external/wpt/webaudio/the-audio-api/the-mediaelementaudiosourcenode-interface/mediaElementAudioSourceToScriptProcessorTest.html [ Timeout ]
 crbug.com/626703 [ Mac10.13 ] external/wpt/webauthn/interfaces.https.html [ Timeout ]
 crbug.com/626703 external/wpt/webrtc/RTCPeerConnection-setLocalDescription-rollback.html [ Timeout ]

third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-audioparam-interface/idl-test.html

@@ -6,7 +6,6 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/resources/idlharness.js"></script>
 <script src="/resources/WebIDLParser.js"></script>
-<script src="/webaudio/js/helpers.js"></script>
 <style type="text/css">
     #audio-param-idl
     { visibility:hidden; height: 0px;}
@@ -43,7 +42,7 @@
   <script>
 (function() {
   var idl_array = new IdlArray();
-  idl_array.add_untested_idls(document.getElementById("audio-param-idl").textContent);
+  idl_array.add_idls(document.getElementById("audio-param-idl").textContent);
 
   delay_time = (new AudioContext).createDelay().delayTime;
 

third_party/WebKit/LayoutTests/external/wpt/webaudio/the-audio-api/the-mediaelementaudiosourcenode-interface/mediaElementAudioSourceToScriptProcessorTest.html

@@ -85,6 +85,7 @@ function processListener (e) {
    // firefox seems to process events after disconnect
    processor.removeEventListener('audioprocess', processListener)
 
+   // Note: the expected result is from a mono source file.
    var expectedBuffer = expected[0];
 
    // Trim the actual elements because we don't have a fine-grained
@@ -110,7 +111,7 @@ function processListener (e) {
        "comparing expected and rendered buffers (channel 0)");
      assert_array_approx_equals(
        actualTrimmedC1,
-       trimEmptyElements(expectedBuffer.getChannelData(1)),
+       trimEmptyElements(expectedBuffer.getChannelData(0)),
        1e-4,
        "comparing expected and rendered buffers (channel 1)");
    }, "All data processed correctly");