Expose scroll customization for touch to JS (behind REF).

Source/core/dom/Element.idl

Index: Source/core/dom/Element.idl
diff --git a/Source/core/dom/Element.idl b/Source/core/dom/Element.idl
index e16fbb87d0d3278386f13f82c09e9679e4207408..49ec1efef1a08e116414fa2882e209176b04b206 100644
--- a/Source/core/dom/Element.idl
+++ b/Source/core/dom/Element.idl
@@ -117,6 +117,10 @@
     void blur();
 
     // Non-standard APIs
+    // Experimental ScrollCustomization API

[Rick Byers, 2015/04/10 14:51:44]

move this below the below methods (this isn't part of the 'non-standard APIs'
referred to by the above comment - the intent is that it will become standard).

Would be nice to add a bug link for more details on the experiment status.

[tdresser, 2015/05/08 18:23:02]

Moved up, not down, as it leaves the standard APIs contiguous.

Added bug link.

+    [RuntimeEnabled=ScrollCustomization] void applyScroll(ScrollState scrollState);

[Rick Byers, 2015/04/10 14:51:44]

Now that attributes are exposed on the prototype chain, can we do this properly
and make these function-type attributes instead of operations?  You can now
explicitly add the '[ExposeJSAccessors]' attribute to make it clear these
attributes must have getters/setters on the prototype chain (regardless of the
default setting).

This will of course change (hopefully vastly simplify) your bindings logic.  But
my understanding is that there's no longer any reason to depend on the old
broken behavior.

[tdresser, 2015/05/08 18:23:02]

I'm not convinced this is a simplification, but I think it is the right thing to
do.

Done, though there will likely need to be some refactoring done in the bindings
logic before landing.

+    [RuntimeEnabled=ScrollCustomization] void distributeScroll(ScrollState scrollState);
+
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=19962
     [RaisesException, CustomElementCallbacks, MeasureAs=InsertAdjacentElement] Element insertAdjacentElement(DOMString where, Element element);
     [RaisesException, MeasureAs=InsertAdjacentText] void insertAdjacentText(DOMString where, DOMString text);