This CL make transform AddBlockAttribute always try to wrap types used
by buffer variables into a struct, in order to generate valid GLSL code
for assigning one buffer struct variable to another buffer struct
variable.
Fixed: tint:1735
Change-Id: I009d8a9ca7ecea1dc0ad6164275c964a18acb33f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/108023
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>
