Move policy code into components/policy.

Move policy code into components/policy.

The code moved to component/policy can be included on iOS, but can't depend
on chrome/. This move includes an exception for the policy protobufs:

- the generic cloud policy protobufs will be moved into a new repository,
  due to a dependency from a ChromeOS package

- the user cloud policy protobuf and its decoding will move into a new component
  for user policy

BUG=271392
TBR=jochen@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=239399

[Joao da Silva, 2013-12-08 21:10:19]

Committed patchset #4 manually as r239399.

[Joao da Silva, 2013-12-08 21:20:09]

After-the-fact comments:

This gigantic CL moves a lot of code from chrome/browser/policy to
components/policy. I've built it on Windows (ninja and msvs), Linux, ChromeOS,
Mac, Android and iOS; the try bots are mostly green too. I'll watch the tree in
the next hour.

Since the patch was so big, git-cl uploaded a patch per file and there is no
sane order to look at this. I think that the gyp changes show the gist of it.

Other changes:

- components/policy is relying on protobufs that come from chrome/browser for
cloud policy; it is a TODO to remove those DEPS exceptions (this work is
underway)

- components_unittests don't have the same setup as unittests. In particular,
ChromeTestSuite loads the ResourceBundle but components_unittests doesn't; so
tests that touch l10n_util function would crash, and have remained behind. It's
a TODO to move them later.

- policy_components is always included in all builds for simplicity, and
includes its sources conditionally on configuration_policy==1; but its
dependencies were always coming in, which caused iOS to include unnecessary
targets. This has been fixed.

- google_apis pulls in dynamic_annotations and it isn't obvious why the build
was failing. Basically static_libraries either have to export their
dependencies, or the dependent needs to declare them again.

- added more DEPS restrictions inside components/policy, in particular to
prevent common/ code from including browser/ code

A lot of subsequent changes depend on this giant CL; if there are comments then
I'll gladly address them in a follow-up CL, unless this breaks the tree.