Chromoting needs null GPO provider in PolicyLoaderWin.

Making Chromoting use no GPO provider in PolicyLoaderWin.

The old Chromoting code (policy_hack before crrev.com/830193002) used to
always read Chromoting policies from the registry.  The new code (using
components/policy) ignores contents of the registry on non-domain-joined
machines.  This old-vs-new difference in behavior was unintentional.
The current changelist ensures that Chromoting's old behavior is preserved.

BUG=460734
TEST=1) components_unittests.exe, 2) remoting_unittests.exe, 3) remoting_unittests.exe --gtest_filter=*PolicyWatcher*Real* -v=1 copied and run from a non-domain-joined, test VM to verify that Chromoting gets its policies from the registry (HKLM\SOFTWARE\Policies\Google\Chrome) in this scenario.

Committed: https://crrev.com/bccb49e3a1864e703a01beabaf9961f215956dea
Cr-Commit-Position: refs/heads/master@{#317865}

[Łukasz Anforowicz, 2015-02-24 00:02:19]

Patchset #2 (id:20001) has been deleted

[Łukasz Anforowicz, 2015-02-24 00:02:24]

Patchset #1 (id:1) has been deleted

[Łukasz Anforowicz, 2015-02-24 00:04:57]

lukasza@chromium.org changed reviewers:
+ mnissler@chromium.org

[Łukasz Anforowicz, 2015-02-24 00:04:57]

Mattias, could you please take a look?

[Mattias Nissler (ping if slow), 2015-02-24 08:09:56]

LGTM

[Łukasz Anforowicz, 2015-02-24 17:06:00]

lukasza@chromium.org changed reviewers:
+ dcaiafa@chromium.org

[Łukasz Anforowicz, 2015-02-24 17:06:01]

Dan, could you please take a look?

[dcaiafa, 2015-02-24 19:11:22]

lgtm

[Łukasz Anforowicz, 2015-02-24 19:14:35]

The CQ bit was checked by lukasza@chromium.org

[commit-bot: I haz the power, 2015-02-24 19:15:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/947353002/40001

[commit-bot: I haz the power, 2015-02-24 20:10:40]

Committed patchset #1 (id:40001)

[commit-bot: I haz the power, 2015-02-24 20:11:12]

Patchset 1 (id:??) landed as
https://crrev.com/bccb49e3a1864e703a01beabaf9961f215956dea
Cr-Commit-Position: refs/heads/master@{#317865}