Remove CapsMap from IR Generator.

Previously, the IRGenerator's fCapsMap was a lookup table from caps-name
to caps-value.

This has been replaced with a lookup table from caps-name to
caps-lookup-method. This is more general-purpose; you can initialize it
once and it always works, instead of needing to initialize it based on
a static set of caps.

The next step after this CL is to migrate this logic into Settings and
remove caps handling from the IR Generator entirely.

Change-Id: I09fc8220f8d5bf297033adbaf4c955f2ce0589cf
Bug: skia:11365, skia:11319
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/375074
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed