Implement select listbox using shadow DOM

LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-listbox.html

Index: LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-listbox.html
diff --git a/LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-listbox.html b/LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-listbox.html
index b4259bf491da0d3aa4e495ab7dbf7ce5dd8bce16..7e1e46b83c9a49dc39fb31d0f7809f50276ea753 100644
--- a/LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-listbox.html
+++ b/LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-listbox.html
@@ -57,8 +57,8 @@
             eventSender.gestureScrollUpdateWithoutPropagation(0, -10);
             eventSender.gestureScrollEnd(0, 0);
 
-            debug("Flinging the list box should scroll the list, the scrolls should be locked to item boundaries");
-            shouldBe('box.scrollTop', '2*itemHeight');
+            debug("Flinging the list box should scroll the list");
+            shouldBe('box.scrollTop', '2*itemHeight+10');

[keishi, 2014/06/22 11:59:55]

Old listbox could only scroll in itemHeight increments but now we have smooth
scroll.

             shouldBe('container.scrollTop', '0');
 
             resetScroll();
@@ -102,8 +102,8 @@
             eventSender.gestureScrollUpdate(0, -6);
             eventSender.gestureScrollEnd(0, 0);
 
-            debug("Gesture scrolling list should scroll the list, the scrolls should lock to item boundaries");
-            shouldBe('box.scrollTop', '3*itemHeight');
+            debug("Gesture scrolling list should scroll the list");
+            shouldBe('box.scrollTop', '3*itemHeight+6');
             shouldBe('container.scrollTop', '0');
 
             resetScroll();