Only execute default actions on trusted events.

LayoutTests/fast/events/wheelevent-in-scrolling-div.html

Index: LayoutTests/fast/events/wheelevent-in-scrolling-div.html
diff --git a/LayoutTests/fast/events/wheelevent-in-scrolling-div.html b/LayoutTests/fast/events/wheelevent-in-scrolling-div.html
index e0cacc3e4b08f4a34f2d6fae9ab5cb0a75dfad27..2b935fb13333a8bebbe0f4ad393467220c6066ed 100644
--- a/LayoutTests/fast/events/wheelevent-in-scrolling-div.html
+++ b/LayoutTests/fast/events/wheelevent-in-scrolling-div.html
@@ -16,16 +16,9 @@
                 if (overflowElement) {
                     overflowElement.addEventListener("mousewheel", mousewheelHandler, false);
 
-                    var deltaX = window.expectedScrollLeft;
-                    var deltaY = window.expectedScrollTop;
-                    var eventInit = {
-                        deltaX: deltaX,
-                        deltaY: deltaY,
-                        wheelDeltaX: -120 * deltaX,
-                        wheelDeltaY: -120 * deltaY,
-                    };
-                    var event = new WheelEvent("mousewheel", eventInit);
-                    overflowElement.dispatchEvent(event);
+                    // EventSender uses 40px per tick.
+                    eventSender.mouseMoveTo(overflowElement.offsetLeft + 5, overflowElement.offsetTop + 5);
+                    eventSender.mouseScrollBy(-2.5, -5);
                 }
 
                 setTimeout('checkOffsets();', 100);
@@ -46,13 +39,13 @@
                 event = e;
                 shouldBe("event.deltaY", "window.expectedScrollTop");
                 shouldBe("event.deltaX", "window.expectedScrollLeft");
-                shouldBe("event.wheelDeltaY", "window.expectedScrollTop*-120");
-                shouldBe("event.wheelDeltaX", "window.expectedScrollLeft*-120");
+                shouldBe("event.wheelDeltaY", "-5*120");
+                shouldBe("event.wheelDeltaX", "-2.5*120");
 
                 if (e.wheelDeltaY)
-                    shouldBe("event.wheelDelta", "window.expectedScrollTop*-120");
+                    shouldBe("event.wheelDelta", "-5*120");
                 else
-                    shouldBe("event.wheelDelta", "window.expectedScrollLeft*-120");
+                    shouldBe("event.wheelDelta", "-2.5*120");
             }
         </script>
     </head>