This code always allocates a new memory buffer for the texture memory,
picks a load function to copy/convert the input data into it, and the
uploads.

In the case where the input format matches the upload format we should
be able to skip the allocation and copy and be much happier.

Change-Id: I8b8c106e0d397bef1c4bcfdb0df60669030776a3
Reviewed-on: https://chromium-review.googlesource.com/293742Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
Tryjob-Request: Geoff Lang <geofflang@chromium.org>