FrameView::autoSizeIfEnabled() should not save a RenderView* or RenderBox* before calling updateLayoutIgnorePendingStylesheets

This code was saving RenderObject pointers on the stack right before calling
updateLayoutIgnorePendingStylesheets which can do a recalcStyle and then
blow away those renderers. Instead we should not get the renderers until
after updating style and layout.

BUG=343050

Review URL: https://codereview.chromium.org/161723002

git-svn-id: svn://svn.chromium.org/blink/trunk@167056 bbb929c8-8fbe-4397-9dbb-9b2b20218538