Disallow local function prototypes Function prototypes should not be allowed inside other functions according to ESSL 3.00.4 section 4.2.4. BUG=angleproject:1068 TEST=angle_unittests, dEQP-GLES*.functional.shaders.functions.invalid.local_function_proto* Change-Id: I54160da4d49b92a6cd7cbee020e67733963d4e10 Reviewed-on: https://chromium-review.googlesource.com/320091 Tryjob-Request: Olli Etuaho <oetuaho@nvidia.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Tested-by: Olli Etuaho <oetuaho@nvidia.com>