Mark MemoryBuffer allocation functions as NO_DISCARD Not all call sites were checking the return value of MemoryBuffer::resize, mark the return value as NO_DISCARD and fix all the warnings. BUG=chromium:1030835 Change-Id: I762796e3d11efc131a814069d78a195b0d4c9f8f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2028151 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>