Move middle-click autoscroll to synthetic fling.

third_party/WebKit/LayoutTests/fast/events/resources/middleClickAutoscroll.js

 var autoscrollInterval = 50;
 var middleButton = 1;
 var middleClickAutoscrollRadius = 15; // from FrameView::noPanScrollRadius
 
 window.jsTestIsAsync = true;
 
 function $(id)
 {
     return document.getElementById(id);
 }
@@ skipping 32 matching lines @@
         if (noModeScroll) {
             testFailed('still autoscroll');
             finishTest();
             return;
         }
 
         if (scrolled)
             return;
         scrolled = true;
         testPassed('autoscroll started');
+        var cursorInfo = window.internals.getCurrentCursorInfo();
+        debug("Mouse cursor shape: " + cursorInfo);
 
         if (window.eventSender) {
             if (param.clickOrDrag == 'click')
                 eventSender.mouseDown(middleButton);
             eventSender.mouseUp(middleButton);
         }
     };
 
     scrollable.ownerDocument.onmouseup = function(e) {
         if (!scrolled || e.button != middleButton)
             return;
         noMoreScroll = true;
         window.setTimeout(function() {
             testPassed('autoscroll stopped');
+            var cursorInfo = window.internals.getCurrentCursorInfo();
+            if (cursorInfo == "type=Pointer hotSpot=0,0" || cursorInfo == "type=IBeam hotSpot=0,0")
+                 testPassed('Mouse cursor cleared');
+            else
+                 testFailed('Mouse cursor shape: ' + cursorInfo);
+
             finishTest();
         }, autoscrollInterval * 2);
     };
 
     if (!window.eventSender)
         return;
     var startX = param.startX || scrollable.offsetLeft + 5;
     var startY = param.startY || scrollable.offsetTop + 5;
     var endX = param.endX || scrollable.offsetLeft + 5;
     var endY = param.endY || scrollable.offsetTop + middleClickAutoscrollRadius + 6;
     eventSender.mouseMoveTo(startX, startY);
     eventSender.mouseDown(middleButton);
     if (param.clickOrDrag == 'click')
         eventSender.mouseUp(middleButton);
     eventSender.mouseMoveTo(endX, endY);
 }