Attempting to paper over all the MSL standard library holes for packed_vector in the MSL writer added complexity to the writer, produced messy output, and didn't actually catch all the cases where casts were needed.
Add a new PackedVec3 transform that applies the packed_vector -> vec casts in a smarter, more precise way.
Fixed: tint:1534
Change-Id: I73ce7e5a62fbc9cb04e1093133070f5fb8965dce
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/107340
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@chromium.org>
a92f4259d5