Previously, once a dynamic buffer had an associated static data, it would
be considered as static and the static data would be always be
reinitialized just after having been invalidated.

BUG=510585

Change-Id: I403e91d35d11efe17f52947b2182f7b8febd7922
Reviewed-on: https://chromium-review.googlesource.com/288351Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>