Adding libjingle dependency to message_lib.gyp

Content IPC message using a libjingle strucrure which is
introduced in here https://codereview.chromium.org/184813006/

This causing some LKGR bots to fail (ASAN). This should fix
those bots.

R=tsepez@chromium.org, inferno@chromium.org

Review URL: https://codereview.chromium.org/185993002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254529 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254529