This change moves most of SerialQueue into SerialStorage
and factors it to make SerialMap and SerialQueue. SerialMap
does not enforce that items are Enqueue'd in monotonically
increasing order. This is useful for implement timeline fences
because OnCompletion callbacks may be added in an arbitrary order.
Bug: dawn:26
Change-Id: I03376117311112b0b94ed887a31974f36c4a5464
Reviewed-on: https://dawn-review.googlesource.com/c/2720
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
