As discussed in blink-dev mailing list remove getPropertyShorthand and isImplicit from the Web expo…

LayoutTests/fast/backgrounds/repeat/resources/background-repeat-shorthand.js

-description('This layout test used to test that correct shorthand name ' + 
-            'is returned for background-repeat-x, ' +
-            'background-repeat-y, background-position-x, background-position-y, ' +
-            '-webkit-mask-repeat-x,-webkit-mask-repeat-y, -webkit-mask-position-x, ' +
-            '-webkit-mask-position-y when corresponding shorthand is used in the style ' +
-            'declaration. It tests regression described in ' +
-            '<a href="https://bugs.webkit.org/show_bug.cgi?id=28972">this bug</a>.' +
-            ' Now that access to non author stylesheet is blocked, we should instead' +
-            ' get null when accessing the css rules on that object.');
-
-function getShorthand(longhand, iconId)
-{
-    var iconDiv = document.getElementById(iconId);
-    var rules = window.getMatchedCSSRules(iconDiv,'',false);
-    return rules[1] ? rules[1].style.getPropertyShorthand(longhand) : 'null';
-}
-
-shouldBe('getShorthand("background-repeat-x", "icon1")', '"null"');
-shouldBe('getShorthand("background-repeat-y", "icon1")', '"null"');
-shouldBe('getShorthand("background-repeat", "icon1")', '"null"');
-
-shouldBe('getShorthand("background-position-x", "icon1")', '"null"');
-shouldBe('getShorthand("background-position-y", "icon1")', '"null"');
-shouldBe('getShorthand("background-position", "icon1")', '"null"');
-
-shouldBe('getShorthand("-webkit-mask-repeat-x", "icon1")', '"null"');
-shouldBe('getShorthand("-webkit-mask-repeat-y", "icon1")', '"null"');
-shouldBe('getShorthand("-webkit-mask-repeat", "icon1")', '"null"');
-
-shouldBe('getShorthand("-webkit-mask-position-x", "icon1")', '"null"');
-shouldBe('getShorthand("-webkit-mask-position-y", "icon1")', '"null"');
-shouldBe('getShorthand("-webkit-mask-repeat", "icon1")', '"null"');
-
-
-shouldBe('getShorthand("background-repeat-x", "icon2")', '"null"');
-shouldBe('getShorthand("background-repeat-y", "icon2")', '"null"');
-shouldBe('getShorthand("background-repeat", "icon2")', '"null"');
-
-shouldBe('getShorthand("background-position-x", "icon2")', '"null"');
-shouldBe('getShorthand("background-position-y", "icon2")', '"null"');
-shouldBe('getShorthand("background-position", "icon2")', '"null"');
-
-shouldBe('getShorthand("-webkit-mask-repeat-x", "icon2")', '"null"');
-shouldBe('getShorthand("-webkit-mask-repeat-y", "icon2")', '"null"');
-shouldBe('getShorthand("-webkit-mask-repeat", "icon2")', '"null"');
-
-shouldBe('getShorthand("-webkit-mask-position-x", "icon2")', '"null"');
-shouldBe('getShorthand("-webkit-mask-position-y", "icon2")', '"null"');
-shouldBe('getShorthand("-webkit-mask-repeat", "icon2")', '"null"');