Move the map logic to the buffer storage implementation.

Refactoring patch only.

BUG=angle:511

Change-Id: Id69efe15ecb32d711a79cc5ff612853e29377368
Reviewed-on: https://chromium-review.googlesource.com/193242
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
1 file changed