[BlackBerry] Main page is rendered at wrong large scale after back from any zooming article at read.thestar.com
https://bugs.webkit.org/show_bug.cgi?id=114296

Patch by Jacky Jiang  <zhajiang@rim.com>.
Reviewed by Rob Buis.

PR: 308655
We were relying on the load state Committed to reset m_userPerformedManualZoom
and m_userPerformedManualScroll; however, the main resources of the
articles on read.thestar.com were preloaded and the WebPage didn't get
any load state change callbacks when going back to the main page from
the articles. Therefore, m_userPerformedManualZoom had never been reset
in this case and we picked up the wrong scale when restoring the main page.
Rset m_userPerformedManualScroll and m_userPerformedManualScroll when
we are going back or forward.

* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPage::goBackOrForward):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148041 268f45cc-cd09-0410-ab3c-d52691b4dbfc