WKPDFView paints rotated pages squished

WKPDFView paints rotated pages squished
https://bugs.webkit.org/show_bug.cgi?id=135401
<rdar://problem/17173916>

Reviewed by Simon Fraser.

* UIProcess/ios/WKPDFView.mm:
(-[WKPDFView _computePageAndDocumentFrames]):
[page size] returns the crop box's size, ignoring rotation.
[page cropBoxAccountForRotation] respects rotation, but otherwise returns the same size.
UIPDFPageView will respect rotation when painting, so we
should make sure that it is given an aspect ratio that also
respects rotation, so that the page isn't squished.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@171775 268f45cc-cd09-0410-ab3c-d52691b4dbfc