Merge 105386 - REGRESSION(r100111): A 'change' event does not fire when a mouse drag

LayoutTests/fast/forms/resources/common.js

 function $(id) {
     return document.getElementById(id);
 }
 
 function getValidationMessageBubbleNode(host) {
     // FIXME: We should search for a pseudo ID.
     return internals.shadowRoot(host).lastChild;
 }
 
 function getAbsoluteRect(element) {
     var rect = element.getBoundingClientRect();
     rect.top += document.body.scrollTop;
     rect.bottom += document.body.scrollTop;
     rect.left += document.body.scrollLeft;
     rect.right += document.body.scrollLeft;
     return rect;
 }
 
 function searchCancelButtonPosition(element) {
     var pos = {};
     pos.x = element.offsetLeft + element.offsetWidth - 9;
     pos.y = element.offsetTop + element.offsetHeight / 2;
     return pos;
 }
+
+function mouseMoveToIndexInListbox(index, listboxId) {
+    var listbox = document.getElementById(listboxId);
+    var itemHeight = Math.floor(listbox.offsetHeight / listbox.size);
+    var border = 1;
+    var y = border + index * itemHeight;
+    if (window.eventSender)
+        eventSender.mouseMoveTo(listbox.offsetLeft + border, listbox.offsetTop + y - window.pageYOffset);
+}