This ASSERT was being overly restrictive, when the code would work correctly when reading from system memory storage as well as staging. BUG=angleproject:1555 Change-Id: Ib45185d8c127a1fb2ce54db9e96fe41d68d5ff2e Reviewed-on: https://chromium-review.googlesource.com/402269Reviewed-by: Zhenyao Mo <zmo@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>
