Port the Simple_VertexShader sample to the new sample framework. Add a Matrix type and cube gemetry generation helper functions. BUG=angle:521 Change-Id: Ia50be1790d6f440499eea052f427762637f3c876 Reviewed-on: https://chromium-review.googlesource.com/188727 Reviewed-by: Shannon Woods <shannonwoods@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>