Update Window API for CSSOM smooth scrolling to match the spec

Source/core/frame/Window.idl

Index: Source/core/frame/Window.idl
diff --git a/Source/core/frame/Window.idl b/Source/core/frame/Window.idl
index a17e69079ecb05962e618f149dfd66c83f473a46..6e538427116cd5b76927661edfc7d543f50b288c 100644
--- a/Source/core/frame/Window.idl
+++ b/Source/core/frame/Window.idl
@@ -95,14 +95,12 @@
     readonly attribute double pageXOffset;
     readonly attribute double pageYOffset;
 
-    // Overloading can be replaced by optional if RuntimeEnabled is removed, by
-    // changing the third argument to *optional* Dictionary scrollOptions
     void scrollBy(double x, double y);
-    [RuntimeEnabled=CSSOMSmoothScroll, RaisesException] void scrollBy(double x, double y, ScrollOptions scrollOptions);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scrollBy([Default=Undefined] optional ScrollToOptions scrollToOptions);
     void scrollTo(double x, double y);
-    [RuntimeEnabled=CSSOMSmoothScroll, RaisesException] void scrollTo(double x, double y, ScrollOptions scrollOptions);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scrollTo([Default=Undefined] optional ScrollToOptions scrollToOptions);
     void scroll(double x, double y);
-    [RuntimeEnabled=CSSOMSmoothScroll, RaisesException] void scroll(double x, double y, ScrollOptions scrollOptions);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scroll([Default=Undefined] optional ScrollToOptions scrollOptions);
     void moveBy([Default=Undefined] optional float x, [Default=Undefined] optional float y); // FIXME: this should take longs not floats.
     void moveTo([Default=Undefined] optional float x, [Default=Undefined] optional float y); // FIXME: this should take longs not floats.
     void resizeBy([Default=Undefined] optional float x, [Default=Undefined] optional float y); // FIXME: this should take longs not floats.