Fix bounds computation bugs responsible for http://bugs.webkit.org/show_bug.cgi?id...

Fix bounds computation bugs responsible for bugs.webkit.org/show_bug.cgi?id=16015
and other image repaint bugs.

Reviewed by Beth Dakin.

We now cache the full local bounds for the <image> element, as otherwise certain
combinations of attribute changes could result in incorrect dirty rects.
Additionally we no longer use any of the integer bounds fields on RenderObject for
determining repaint bounds (this was the principle cause of bug #16015).

I also removed the outline painting code as it was both wrong, and not correctly
repainted.  I feel safe doing this as no other browser or viewer supports outline
properties on svg elements.

I was unable to make a testcase for this unfortunately, despite seemingly deterministic
behaviour :(

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@29192 268f45cc-cd09-0410-ab3c-d52691b4dbfc