Import wpt@ed94c51f3dfaa5ff4c9c311add1a560408059c51

third_party/WebKit/LayoutTests/imported/wpt/web-animations/testcommon.js

 /*
 Distributed under both the W3C Test Suite License [1] and the W3C
 3-clause BSD License [2]. To contribute to a W3C Test Suite, see the
 policies and contribution forms [3].
 
 [1] http://www.w3.org/Consortium/Legal/2008/04-testsuite-license
 [2] http://www.w3.org/Consortium/Legal/2008/03-bsd-license
 [3] http://www.w3.org/2004/10/27-testcases
  */
 
-"use strict";
+'use strict';
+
 var MS_PER_SEC = 1000;
 
+// The recommended minimum precision to use for time values[1].
+//
+// [1] https://w3c.github.io/web-animations/#precision-of-time-values
+var TIME_PRECISION = 0.0005; // ms
+
+// Allow implementations to substitute an alternative method for comparing
+// times based on their precision requirements.
+if (!window.assert_times_equal) {
+  window.assert_times_equal = function(actual, expected, description) {
+    assert_approx_equals(actual, expected, TIME_PRECISION, description);
+  }
+}
+
 // creates div element, appends it to the document body and
 // removes the created element during test cleanup
 function createDiv(test, doc) {
   if (!doc) {
     doc = document;
   }
   var div = doc.createElement('div');
   doc.body.appendChild(div);
   test.add_cleanup(function() {
     div.remove();
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     function handleFrame() {
       if (--frameCount <= 0) {
         resolve();
       } else {
         window.requestAnimationFrame(handleFrame); // wait another frame
       }
     }
     window.requestAnimationFrame(handleFrame);
   });
 }