Add support creating and saving a new reference file.

third_party/WebKit/LayoutTests/webaudio/AudioBufferSource/audiobuffersource-playbackrate-modulation.html

Index: third_party/WebKit/LayoutTests/webaudio/AudioBufferSource/audiobuffersource-playbackrate-modulation.html
diff --git a/third_party/WebKit/LayoutTests/webaudio/AudioBufferSource/audiobuffersource-playbackrate-modulation.html b/third_party/WebKit/LayoutTests/webaudio/AudioBufferSource/audiobuffersource-playbackrate-modulation.html
index 89d3e3c9b1babe5a381e4a9bc6be4b215b35218a..45e1f2906a2e39fc8dd6b9ddca87e101feb370e3 100644
--- a/third_party/WebKit/LayoutTests/webaudio/AudioBufferSource/audiobuffersource-playbackrate-modulation.html
+++ b/third_party/WebKit/LayoutTests/webaudio/AudioBufferSource/audiobuffersource-playbackrate-modulation.html
@@ -55,49 +55,17 @@
           thresholdDiffCount: 0,
           bitDepth: 16
         });
-
+        if (!window.testRunner) {
+          // Always save the generated results if we're running in a browser.
+          var filename = 'audiobuffersource-playbackrate-modulation-actual.wav';
+          downloadAudioBuffer(renderedBuffer, filename);
+          Should("Saved", true)
+            .summarize(filename, "");
+        }

[hongchan, 2017/03/03 18:39:25]

This section can be abstracted a function:

bool generateReferenceFileForBrowser(buffer, name);

[Raymond Toy, 2017/03/03 18:43:10]

Yes and no.  For old Audit, Should is just a function.  But for new Audit, we'd
have to pass in the should function.  Just pass in Should (or should) as an
additional arg?

       }).then(done);
     });
 
-    // Task: Create a new reference audio file. See .runTasks() below to run
-    // this task.
-    audit.defineTask('generate-reference', function (done) {
-      if (!window.testRunner) {
-        done();
-        return;
-      }
-
-      // With this setting, the playback rate will be changing continuously and
-      // repeatedly within the range of [0, 200] around 100Hz, based on the
-      // input from the oscillator.
-      createSawtoothWithModulation(context, 'playbackRate', 100, 100);
-
-      // |finishAudioTest| will automatically create a reference audio file from
-      // the OAC rendering if the reference file does not exist.
-      context.oncomplete = finishAudioTest;
-      context.startRendering();
-      testRunner.waitUntilDone();
-
-      done();
-    });
-
-    audit.defineTask('finish', function (done) {
-      done();
-    });
-
-    window.onload = function () {
-      audit.runTasks(
-        'load-reference',
-        'generate-verify',
-        'finish'
-      );
-    };
-
-    // Use this task to generate a new reference audio file. Make sure to
-    // comment out .runTasks() above before use this.
-    // audit.runTasks('generate-reference');
-
-    successfullyParsed = true;
+    audit.runTasks();
   </script>
 </body>