Unreviewed Mac gardening after r170817.

* platform/mac-wk2/TestExpectations:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170846 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Add test to ensure that SVGDocumentExtensions::rebuildElements() doesn't rebuild invalid elements
https://bugs.webkit.org/show_bug.cgi?id=134417
<rdar://problem/17479854>

Reviewed by David Kilzer.

Add a test that implicitly checks that the list of SVG elements to be rebuilt doesn't contain
removed elements. Run this test in DRT with Guard Malloc/MallocScribble (or the platform-
specific equivalent) enabled.

* svg/custom/overwrite-page-that-has-use-elements-expected.txt: Added.
* svg/custom/overwrite-page-that-has-use-elements.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170847 268f45cc-cd09-0410-ab3c-d52691b4dbfc
update-webkitgtk-libs script fails by unsatisfied dependencies
https://bugs.webkit.org/show_bug.cgi?id=134547

Reviewed by Martin Robinson.

Install libxcb-xfixes0-dev, needed to build Mesa.

* gtk/install-dependencies:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170848 268f45cc-cd09-0410-ab3c-d52691b4dbfc