Makes LinkProgram fail if both a vertex and fragment shader
are not present.  Desktop GL doesn't fail this case because
the fixed function pipeline can be a substitute for either

TEST=unit tests
BUG=none

Review URL: http://codereview.chromium.org/2582002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49073 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed