test_shell: fix for newer cairos
test_shell: fix for newer cairos

We need to call cairo_surface_mark_dirty to let Cairo know that
we've twiddled the pixels without its knowledge.  Without this,
on current Cairo versions, test_shell's web widget shows up as
a gray box.

Review URL: http://codereview.chromium.org/2982002

git-svn-id: http://src.chromium.org/svn/trunk/src@52225 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 0f1bdbf1084797df7567428029239c966be08dba
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser