Allows error handling in these functions. Necessary for the Vulkan
back-end.

Bug: angleproject:4209
Change-Id: I2092e58e719c6ee562807e1c7e8ad26988342855
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2040196Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>