Remove stale RFHM check now that unload runs in the background.

Remove stale RFHM check now that unload runs in the background.

BUG=402020
TEST=No behavior change.

Committed: https://crrev.com/52538dfb0dee9307b87bb688569ec23893a14cab
Cr-Commit-Position: refs/heads/master@{#297688}

[Charlie Reis, 2014-10-01 17:41:58]

creis@chromium.org changed reviewers:
+ nasko@chromium.org

[Charlie Reis, 2014-10-01 17:43:25]

Nasko, can you take a look?  I think this is dead code, and I'm just waiting on
the test results.

[nasko, 2014-10-01 18:06:40]

LGTM

[Charlie Reis, 2014-10-01 18:46:24]

The CQ bit was checked by creis@chromium.org

[commit-bot: I haz the power, 2014-10-01 18:48:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/617273004/1

[commit-bot: I haz the power, 2014-10-01 19:21:17]

Committed patchset #1 (id:1) as ba6632f2335001cafd22a563e5575d6682006437

[commit-bot: I haz the power, 2014-10-01 19:21:59]

Patchset 1 (id:??) landed as
https://crrev.com/52538dfb0dee9307b87bb688569ec23893a14cab
Cr-Commit-Position: refs/heads/master@{#297688}

[Charlie Reis, 2014-10-06 22:39:20]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/632043002/ by creis@chromium.org.

The reason for reverting is: The new CHECK fails if
render_view_host_->is_waiting_for_close_ack_ is true.  See
http://crbug.com/420557..