Layout support for new circle shape syntax

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 63 matching lines @@
     var shapeFunction = s.match(/(\w+)\((.+)\)/);
     if (!shapeFunction)
         return null;
 
     var matches;
     switch (shapeFunction[1]) {
     case "rectangle":
         matches = s.match("rectangle\\((.*)\\s*,\\s*(.*)\\s*,\\s*(.*)\\,\\s*(.*)\\)");
         break;
     case "circle":
-        matches = s.match("circle\\((.*)\\s*,\\s*(.*)\\s*,\\s*(.*)\\)");
+        matches = s.match("circle\\((.*)\\s+at\\s+(.*)\\s+(.*)\\)");
         break;
     case "ellipse":
         matches = s.match("ellipse\\((.*)\\s*,\\s*(.*)\\s*,\\s*(.*)\\,\\s*(.*)\\)");
         break;
     case "polygon":
         matches = s.match("polygon\\(nonzero, (.*)\\s+(.*)\\s*,\\s*(.*)\\s+(.*)\\s*,\\s*(.*)\\s+(.*)\\s*,\\s*(.*)\\s+(.*)\\)");
         break;
     default:
         return null;
     }
@@ skipping 599 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, disablePauseAnimationAPI) {
     isTransitionsTest = true;
     runAnimationTest(expected, callbacks, trigger, disablePauseAnimationAPI, doPixelTest);
 }