java: Add a choreographer frame task trait

This is useful if you need to guarantee something like a layout pass has
occurred before your task runs. Tasks posted with TaskTraits.CHOREOGRAPHER_FRAME
will run next time there's a vsync and after all other ready tasks on the thread
have run.

I put the trait under base because from what I understand there is some ui/ code
that needs it but ui/ can't depend on content/.

Bug: 863341
Change-Id: Ibcb7a843866c2b2c4f4394ebd18c8ef7aa33b5bc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1549114
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Karolina Soltys <ksolt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652215}
6 files changed