[BlackBerry] WebPage doesn't zoom to fit viewport after being rotated from landscape to portrait mode
https://bugs.webkit.org/show_bug.cgi?id=119754

Patch by Jacky Jiang <zhajiang@blackberry.com> on 2013-08-13
Reviewed by Rob Buis.
Internally reviewed by Konrad Piascik.

JIRA 470951
In this case, zoomToFitWidthScale(currentScale) = viewportWidth / contentsWidth
which was 2.6666666666666665, initialScale = ((viewportWidth / devicePixelRatio)
/ contentsWidth) * devicePixelRatio which was 2.6666665077209473. When
rotating the device from landscape to portrait, m_webPage->isAtInitialZoom()
was false in setViewportSize() because of the floating-point rounding error
above so that we had to use the scale of the previous rotation WebPage
which was too large for the current rotation WebPage.
Ignore the floating-point rounding error in isAtInitialZoom() so that we
can use initialScale of the current rotation WebPage as the scale and also
we should do it for isMaxZoomed() and isMinZoomed() as well. Please note
that we can not use FLT_EPSILON here as it's 1E-7 on our platform.

* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::initialScale):
(BlackBerry::WebKit::WebPage::isMaxZoomed):
(BlackBerry::WebKit::WebPage::isMinZoomed):
(BlackBerry::WebKit::WebPage::isAtInitialZoom):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154029 268f45cc-cd09-0410-ab3c-d52691b4dbfc