Make RunLoop::Delegate methods public.

This mimics the pre-existing paradigm for MessagePump::Delegate :
public methods on Delegate which are then privately inherited.

There were cr-dev discussions on these topics (composition vs private
inheritance) but I don't see a reason to deviate from the
pre-established MessagePump paradigm here.
https://groups.google.com/a/chromium.org/d/topic/chromium-dev/XdsXTHy9lis/discussion
https://groups.google.com/a/chromium.org/d/topic/chromium-dev/CwzjcWd9cYM/discussion

I did consider composition here (e.g. with a private RunDelegate
class in MessageLoop, but the many outer_-> in
Run/Quit/EnsureWorkScheduled made it ugly.

R=danakj@chromium.org

Bug: 708584
Change-Id: I42830b3a28d29b1a518db4cfc767a655de491a90
Reviewed-on: https://chromium-review.googlesource.com/798290
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521227}
1 file changed