Move error checking into VarDeclaration::Convert.

We had some error-checking logic in IRGenerator that could trivially
move into VarDeclaration::Convert. It's better to centralize the logic
when we can. (In PS2, I added matching assertion checks to Make.)

Change-Id: If15aeaa501274c4332c9ccec069b7e2ab1137dc9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/442240
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed