Making Chromoting use no 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.

Review URL: https://codereview.chromium.org/947353002

Cr-Commit-Position: refs/heads/master@{#317865}
(cherry picked from commit bccb49e3a1864e703a01beabaf9961f215956dea)

TBR=dcaiafa

Committed: https://chromium.googlesource.com/chromium/src/+/41afc827ec23ff2c52add2f25782ad97b4137f28

[Jamie, 2015-02-26 20:55:23]

Committed patchset #1 (id:1) manually as
41afc827ec23ff2c52add2f25782ad97b4137f28 (presubmit successful).

[dcaiafa, 2015-02-26 22:52:18]

lgtm