sync gles2_call_visitor_autogen.h

mojo/public/c/gles2/gles2_call_visitor_autogen.h is generated by
gpu/command_buffer/build_gles2_cmd_buffer.py, and its contents are out
of sync.

Note: build_gles2_cmd_buffer.py only runs if the chromium ppapi
directory is copied into the mojo tree.

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/830563003