Import wpt@ed94c51f3dfaa5ff4c9c311add1a560408059c51

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

Index: third_party/WebKit/LayoutTests/imported/wpt/web-animations/testcommon.js
diff --git a/third_party/WebKit/LayoutTests/imported/wpt/web-animations/testcommon.js b/third_party/WebKit/LayoutTests/imported/wpt/web-animations/testcommon.js
index ab54202f10eedfaf79be6cc123e9943ac3ccf7bc..5ba03082a9cd65bd7ae916ad99d877e879896484 100644
--- a/third_party/WebKit/LayoutTests/imported/wpt/web-animations/testcommon.js
+++ b/third_party/WebKit/LayoutTests/imported/wpt/web-animations/testcommon.js
@@ -8,9 +8,23 @@ policies and contribution forms [3].
 [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) {