Remove GrProgramDesc::KeyHeader structure

Instead, just fold all of this information into the key, like everything
else. The only value that was accessed elsewhere is the initial key
length. That doesn't need to be part of the key, so store it separately
in the GrProgramDesc.

Removing this special case logic is just the first step in revising how
we assemble keys.

Bug: skia:11372
Change-Id: I52eb76812045e1906797cb37e809cfd0b3332ef0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/376797
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed