https://bugs.webkit.org/show_bug.cgi?id=93983
PR #191737

Reviewed by Yong Li.
Patch by Antonio Gomes <agomes@rim.com>

Patch changes the way we currently keep track of the active scrollable area
objects: before, we acquired the scrollable areas and just passed them in a vector up
to the client, copying it over and over again. Also, it was a client responsability to
delete stuff (BAD!).
Now, we keep track of vector within InRegionScroller, as a class member, which allows us to
avoid copies (in follow up patch), and control until when these objects outlive.

Patch also changes InRegionScrollableArea to "retptr" the composited layer
associated to it (if any). This ensure we have a non-null scrollable element always.

As mentioned, InRegionScroller is now responsible for deleting and vector of scrollable areas.

Internally reviewed by Arvid Nilsson.

* Api/InRegionScroller.cpp:
(WebKit):
(BlackBerry::WebKit::InRegionScrollerPrivate::reset): Method is now responsible for
deleting the tracked scrollable areas.
(BlackBerry::WebKit::InRegionScrollerPrivate::calculateInRegionScrollableAreasForPoint):
Renamed from 'inRegionScrollableAreasForPoint'. It was changed in order to store the
scrollable area objects instead of just pass a copy of them up to the client.
(BlackBerry::WebKit::InRegionScrollerPrivate::activeInRegionScrollableAreas): Getter.
(BlackBerry::WebKit::InRegionScrollerPrivate::pushBackInRegionScrollable): It was
promoted to a class method instead of a local helper.
* Api/InRegionScroller_p.h:
(WebKit):
(InRegionScrollerPrivate):
* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::setScrollOriginPoint): Adjustments needed due to the
above changed.
* WebKitSupport/InRegionScrollableArea.cpp:
(BlackBerry::WebKit::InRegionScrollableArea::~InRegionScrollableArea): Clear up the cached layer.
(WebKit):
(BlackBerry::WebKit::InRegionScrollableArea::InRegionScrollableArea):
* WebKitSupport/InRegionScrollableArea.h:
(InRegionScrollableArea):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@125678 268f45cc-cd09-0410-ab3c-d52691b4dbfc