Linux: Fix about:memory for SUID sandbox + pid namespaces.
Linux: Fix about:memory for SUID sandbox + pid namespaces.

BUG=36934
TEST=about:memory works on Linux machines with pid namespaces enabled.
Review URL: http://codereview.chromium.org/752001

git-svn-id: http://src.chromium.org/svn/trunk/src@41075 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 5ad47bfb51874e0c131b4245f4086e272eb4575e
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