Consolidate all the id handling and caching code.

BUG=skia:7515

Change-Id: Iab31e8cadfaa1ce09d85aab9cc84a3e614ea5e45
Reviewed-on: https://skia-review.googlesource.com/100420
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Herb Derby <herb@google.com>
5 files changed