Use non-default TaskRunner on WebLocks

Mojo interfaces for WebLocks API used to use the default TaskRunner
instead of the frame-associated one. That causes a test failure on
an upcoming change for per-site EventLoop.

This CL updates the interface set up to use per-frame TaskRunner.

Bug: 961186
Change-Id: Icf75d959edc7817a445636d56ec8ffece5b1ceae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1626201
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663028}
1 file changed