Add support for GL_OES_depth32. This will allow ANGLE to be more conformant when it accepts 32-bit depth as a Renderbuffer format. BUG=angleproject:1230 Change-Id: I9336c6f951d280b2332fc3e6d2e640852473aa03 Reviewed-on: https://chromium-review.googlesource.com/313994 Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>