Fix getBBox for perpendicular paths

Fix getBBox for perpendicular paths
https://bugs.webkit.org/show_bug.cgi?id=76177

Patch by Philip Rogers <pdr@google.com> on 2012-01-17
Reviewed by Darin Adler.

Source/WebCore:

Test: svg/custom/getBBox-perpendicular-path.svg

* platform/graphics/FloatRect.cpp:
(WebCore::FloatRect::unite):
(WebCore::FloatRect::uniteEvenIfEmpty):
(WebCore::FloatRect::uniteIfNonZero):
* platform/graphics/FloatRect.h:
* rendering/svg/SVGRenderSupport.cpp:
(WebCore::SVGRenderSupport::computeContainerBoundingBoxes):

LayoutTests:

* svg/custom/getBBox-perpendicular-path-expected.txt: Added.
* svg/custom/getBBox-perpendicular-path.svg: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105231 268f45cc-cd09-0410-ab3c-d52691b4dbfc