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

Source/core/css/CSSStyleDeclaration.idl

Index: Source/core/css/CSSStyleDeclaration.idl
diff --git a/Source/core/css/CSSStyleDeclaration.idl b/Source/core/css/CSSStyleDeclaration.idl
index be7b7082a417d77db7a81565d5be36a55eb10c2c..9efa6b6db1db2c82826f89cadaf16a6e618efc24 100644
--- a/Source/core/css/CSSStyleDeclaration.idl
+++ b/Source/core/css/CSSStyleDeclaration.idl
@@ -39,9 +39,5 @@
     readonly attribute unsigned long    length;
     getter DOMString          item([Default=Undefined] optional unsigned long index);
     readonly attribute CSSRule          parentRule;
-
-    // Extensions
-    [TreatReturnedNullStringAs=Null] DOMString          getPropertyShorthand([Default=Undefined] optional DOMString propertyName);
-    boolean            isPropertyImplicit([Default=Undefined] optional DOMString propertyName);
 };