Pan Scrolling Jumps out of frames if the initial location is in a frame that can't be scrolled.
        
Reviewed by Darin Adler.

WebCore: 

When we initially figure out the layer that we should begin scrolling, don't try to jump out
of frames/iFrames to look at the owner document. We don't want to jump out of frames, so we
don't need that logic anymore.
        
Added a test to make sure that we don't pan scroll if we start to scroll in an empty
iFrame that has a scrollable owner document.

Test: platform/win/fast/events/panScroll-no-iframe-jump.html

* dom/Node.cpp:
(WebCore::Node::defaultEventHandler):

LayoutTests: 

Added a test to make sure that we don't pan scroll if we start to scroll in an empty
iFrame that has a scrollable owner document.

* platform/win/fast/events/panScroll-no-iframe-jump-expected.txt: Added.
* platform/win/fast/events/panScroll-no-iframe-jump.html: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@52012 268f45cc-cd09-0410-ab3c-d52691b4dbfc