Added proper DCHECKs to ensure proper resource provider synchronization.

Proper DCHECKs have been added to make sure resource provider users
add all the proper synchronization calls. All the unittests have also
been fixed up to properly synchronize and insert sync tokens when
necessary.

BUG=584381
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1717873002

Cr-Commit-Position: refs/heads/master@{#378533}
6 files changed