Add webgl checks in GetActiveUniformsiv. Add validation that disallows GL_UNIFORM_NAME_LENGTH from being used. BUG=angleproject:1523 TEST=angle_end2end_tests Change-Id: Id70e25ab79fd93ae4eb8b8343819458a4a0e4a71 Reviewed-on: https://chromium-review.googlesource.com/1187511 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Bryan Bernhart <bryan.bernhart@intel.com> Commit-Queue: Bryan Bernhart <bryan.bernhart@intel.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>