commit 3919aa1b42669eadec4a8489c834edb710ea68c9
author Gabriel Charette <gab@chromium.org> Fri Jun 01 22:55:42 2018
committer Commit Bot <commit-bot@chromium.org> Fri Jun 01 22:55:42 2018
tree 2ea457d0c5f301461ac395c74e895267c59872b8
parent da620acb4996e3f839b5bf35c1c44b1187f40c7b

[MessageLoop] Clear all pending tasks in TriageQueue::Clear

This is a precursor to moving the |incoming_queue_| multi-threaded part
of IncomingTaskQueue to MessageLoopTaskRunner to allow mocking the
source of incoming tasks (i.e. for ScopedTaskEnvironment::MOCK_TIME on
top of MLForUI/etc.).

Such an interface will not have a notion of pre-triaged versus
still-on-multi-threaded-queue tasks. What matters here is that
TriageQueue::Clear() doesn't get stuck in a loop, the new logic clears
all pending tasks while still backing out if destructors post more
tasks.

R=danakj@chromium.org, kylechar@chromium.org

Bug: 708584
Change-Id: I8cd4f244718e4f5f74d5cb84138083ee37833238
Reviewed-on: https://chromium-review.googlesource.com/1078932
Commit-Queue: Gabriel Charette <gab@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563846}