Add task runners to more tests

This patch modifies a number of tests to have a more realistic threading
set-up by either:

a) adding a TestBrowserThreadBundle
b) constructing any existing TestBrowserThreadBundle earlier or
c) adding a MessageLoop as appropriate.

This makes it possible to later migrate base/ from MessageLoopProxy
over to ThreadTaskRunnerHandle, which requires an active task runner on
the current thread.

BUG=465354, 481632
TBR=tommi@chromium.org

Review URL: https://codereview.chromium.org/1105373002

Cr-Commit-Position: refs/heads/master@{#327463}
7 files changed