https://bugs.webkit.org/show_bug.cgi?id=87438

Reviewed by Antonio Gomes.
Patch by Jacky Jiang <zhajiang@rim.com>

PR: 159923
For back/forward history navigation, we were trying to keep the values
set by dispatchViewportDataDidChange. However, when we went back from
the previous page, if the current page didn't contain the meta viewport
tag, then those values set by previous page would never be reset.
Although the current page could get correct saved scale when restoring
view state, the scale would still be clamped by zoomToFitScale which
was based on the virtual viewport of the previous page which could make
the scale incorrect.
Since we know the viewport arguments of the current document before
setLoadState on back/forward history navigation, we can reset these
previous values if the document doesn't have viewport arguments during
setLoadState.

* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::setLoadState):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@118530 268f45cc-cd09-0410-ab3c-d52691b4dbfc