ScrollTopLeftInterop should not be marked experimental

LayoutTests/fast/css/resize-corner-tracking-touch.html

Index: LayoutTests/fast/css/resize-corner-tracking-touch.html
diff --git a/LayoutTests/fast/css/resize-corner-tracking-touch.html b/LayoutTests/fast/css/resize-corner-tracking-touch.html
index 68f536863acb73a662ad90139ee1f66e20f1d4ab..673a3f1b859a401174863e82b3a6ded4e7877ec8 100644
--- a/LayoutTests/fast/css/resize-corner-tracking-touch.html
+++ b/LayoutTests/fast/css/resize-corner-tracking-touch.html
@@ -51,7 +51,7 @@
                 return;
 
             // Scroll the page first to test that resize works with scrolled page.
-            document.documentElement.scrollTop = 50;
+            document.body.scrollTop = 50;
 
             // 1. Touch scrolling starting at outside of the object, e.g. offset (6, 7)
             //    to bottom right corner of the object, won't do the resize.
@@ -67,7 +67,7 @@
             resize("textarea1", -20, -20, 20, 10, "resize");
 
             // Scroll the page again
-            document.documentElement.scrollTop += 100;
+            document.body.scrollTop += 100;
 
             resize("iframe1", -6, -7, 20, 10, "resize");
             resize("iframe1", -20, -20, 20, 10, "resize");