[BlackBerry] Improve Fatfinger phase.
https://bugs.webkit.org/show_bug.cgi?id=107403

Patch by Tiancheng Jiang <tijiang@rim.com> on 2013-05-14
Reviewed by Rob Buis.

Internally reviewed by Genevieve Mak.
BlackBerry PR 324965.

Cache and reuse intersected nodes as long as hit position has not been
changed.

* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::hitTestResult):
* Api/WebPage_p.h:
(WebPagePrivate):
* WebKitSupport/FatFingers.cpp:
(BlackBerry::WebKit::FatFingers::findBestPoint):
(BlackBerry::WebKit::FatFingers::findIntersectingRegions):
(BlackBerry::WebKit::FatFingers::getNodesFromRect):
* WebKitSupport/FatFingers.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150091 268f45cc-cd09-0410-ab3c-d52691b4dbfc