ccpr: Various cleanups

Renames GrCCCoverageProcessor::RenderPass to PrimitiveType and handles
corners as subpasses instead. Various touchups to coverage processors
now that the overhaul is complete. This change should be strictly a
refactor.

Bug: skia:
Change-Id: I52852463330d5ec71fae7e19fadccd9ede8b2c16
Reviewed-on: https://skia-review.googlesource.com/116169
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
7 files changed