Add support for the object-position CSS property.

LayoutTests/animations/resources/animation-test-helpers.js

 /* This is the helper function to run animation tests:
 
 Test page requirements:
 - The body must contain an empty div with id "result"
 - Call this function directly from the <script> inside the test page
 
 Function parameters:
     expected [required]: an array of arrays defining a set of CSS properties that must have given values at specific times (see below)
     callbacks [optional]: a function to be executed immediately after animation starts;
                           or, an object in the form {time: function} containing functions to be
@@ skipping 349 matching lines @@
             property += "-source";
 
         computedValue = window.getComputedStyle(document.getElementById(elementId)).getPropertyCSSValue(property).cssText;
         computedCrossFade = parseCrossFade(computedValue);
 
         if (!computedCrossFade) {
             pass = false;
         } else {
             pass = isCloseEnough(computedCrossFade.percent, expectedValue, tolerance);
         }
+    } else if (property == "object-position") {
+        computedValue = window.getComputedStyle(document.getElementById(elementId)).objectPosition;
+        var actualArray = computedValue.split(" ");
+        var expectedArray = expectedValue.split(" ");
+        if (actualArray.length != expectedArray.length) {
+            pass = false;
+        } else {
+            for (i = 0; i < expectedArray.length; ++i) {
+                pass = isCloseEnough(parseFloat(actualArray[i]), parseFloat(expectedArray[i]), tolerance);
+                if (!pass)
+                    break;
+            }
+        }
     } else {
         var computedStyle = window.getComputedStyle(document.getElementById(elementId)).getPropertyCSSValue(property);
         if (computedStyle.cssValueType == CSSValue.CSS_VALUE_LIST) {
             var values = [];
             for (var i = 0; i < computedStyle.length; ++i) {
                 switch (computedStyle[i].cssValueType) {
                   case CSSValue.CSS_PRIMITIVE_VALUE:
                     values.push(computedStyle[i].getFloatValue(CSSPrimitiveValue.CSS_NUMBER));
                     break;
                   case CSSValue.CSS_CUSTOM:
@@ skipping 309 matching lines @@
     [1] If the CSS property name is "-webkit-transform", expected value must be an array of 1 or more numbers corresponding to the matrix elements,
     or a string which will be compared directly (useful if the expected value is "none")
     If the CSS property name is "-webkit-transform.N", expected value must be a number corresponding to the Nth element of the matrix
 
 */
 function runTransitionTest(expected, trigger, callbacks, doPixelTest) {
     expected = expected.map(function(expectation) { expectation.unshift(null); return expectation; });
     isTransitionsTest = true;
     runAnimationTest(expected, callbacks, trigger, false, doPixelTest);
 }