unit_tests: Fix link error (missing libXi) on Linux
unit_tests: Fix link error (missing libXi) on Linux

unit_tests fails to link due to requirement on libXi. This is implicitly
provided by 'gdk', but unit_tests does not depend on this target. We add
a 'xi' dependency for any target depending on 'x11'.

BUG=63209
TEST=None
(Landing patch for jknotten@chromium.org.)

Review URL: http://codereview.chromium.org/5016001

git-svn-id: http://src.chromium.org/svn/trunk/src@66169 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: af3b6cd444376fc914c56ebd6ad33d48fbe7db8c
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