Mousemove event should be fired when the mouse stays in the document but there is no element.

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index 171447553aa938ac3979a2f714dae86f274fc0e3..4a1c17c5f3370bb94e6a410556300e5303ea0ce1 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -2408,7 +2408,10 @@ bool RenderLayer::hitTest(const HitTestRequest& request, const HitTestLocation&
         // We didn't hit any layer. If we are the root layer and the mouse is -- or just was -- down,
         // return ourselves. We do this so mouse events continue getting delivered after a drag has
         // exited the WebView, and so hit testing over a scrollbar hits the content document.
-        if (!request.isChildFrameHitTest() && (request.active() || request.release()) && isRootLayer()) {
+        // In addtion, the mouse is possible to stay in document but there is no element.
+        // At that time, the events of the mouse should be fired.
+        LayoutPoint hitPoint = hitTestLocation.point();
+        if (!request.isChildFrameHitTest() && ((request.active() || request.release()) || (request.move() && hitTestArea.contains(hitPoint.x(), hitPoint.y()))) && isRootLayer()) {

[Julien - ping for review, 2014/09/19 16:56:41]

Why do we special case mouse move here? Wouldn't mouse clicks or mouse drags
also work?

[Miyoung Shin(g), 2014/09/20 03:59:43]

Mouse click is working well because there is already the condition of
request.active() here.
When I investigated this problem at first, I was wondering why mouse click is
working, then I found this condition.
That's the reason why I changed here.

In case of mouse drag, when I tested it, currently it doesn't work, but if I
apply my patch, it works well.

             renderer()->updateHitTestResult(result, toRenderView(renderer())->flipForWritingMode(hitTestLocation.point()));
             insideLayer = this;
         }