GitLab

This CL (hopefully) removes all calls to these methods in ios:
- MessageLoop::PostTask
- MessageLoop::PostDelayedTask
- MessageLoop::DeleteSoon
- MessageLoop::ReleaseSoon
- MessageLoop::Run
- MessageLoop::RunUntilIdle

BUG=616447
R=sdefresne@chromium.org

Review-Url: https://codereview.chromium.org/2314243002
Cr-Commit-Position: refs/heads/master@{#417305}