Improve documentation for special-purpose policy providers.

Improve documentation for special-purpose policy providers.

ProxyPolicyProvider and ForwardingPolicyProvider seemed to be
similar-purpose judging by the name, but that's far from accurate.
This change adds more documentation and renames
ForwardingPolicyProvider to SchemaRegistryTrackingPolicyProvider in an
attempt to clarify the situation for readers coming after me.

BUG=None
TEST=No functional changes.

Committed: https://crrev.com/050d7d754b374a4d0828aec1ab49d524c5f67ce5
Cr-Commit-Position: refs/heads/master@{#307028}

[Mattias Nissler (ping if slow), 2014-12-05 15:11:50]

mnissler@chromium.org changed reviewers:
+ atwilson@chromium.org, joaodasilva@chromium.org

[Mattias Nissler (ping if slow), 2014-12-05 15:11:50]

Not sure whether Joao is still taking reviews, so adding the two of you :)

[Andrew T Wilson (Slow), 2014-12-05 15:21:04]

lgtm, assuming there are no differences between the two new files and the
deleted forwarding_* files.

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
File components/policy/core/common/BUILD.gn (right):

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
components/policy/core/common/BUILD.gn:73: "../../policy_export.h",
Why is this moved here?

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
File components/policy/core/common/proxy_policy_provider.h (right):

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
components/policy/core/common/proxy_policy_provider.h:21: // Furthermore,
IsInitializationComplete is implemented trivially - it always
nit: IsInitializationComplete() to match the rest of the comment that include ()
for functions.

[Mattias Nissler (ping if slow), 2014-12-05 15:24:49]

Thanks for reviewing. The other changes are indeed just text replacements and
subsequent reformatting where needed.

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
File components/policy/core/common/BUILD.gn (right):

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
components/policy/core/common/BUILD.gn:73: "../../policy_export.h",
On 2014/12/05 15:21:04, Andrew T Wilson wrote:
> Why is this moved here?

Automated sort didn't sort. Reverted.

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
File components/policy/core/common/proxy_policy_provider.h (right):

https://codereview.chromium.org/775613004/diff/1/components/policy/core/commo...
components/policy/core/common/proxy_policy_provider.h:21: // Furthermore,
IsInitializationComplete is implemented trivially - it always
On 2014/12/05 15:21:04, Andrew T Wilson wrote:
> nit: IsInitializationComplete() to match the rest of the comment that include
()
> for functions.

Done.

[Mattias Nissler (ping if slow), 2014-12-05 15:24:52]

The CQ bit was checked by mnissler@chromium.org

[commit-bot: I haz the power, 2014-12-05 15:25:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/775613004/20001

[commit-bot: I haz the power, 2014-12-05 16:15:21]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-12-05 16:16:06]

Patchset 2 (id:??) landed as
https://crrev.com/050d7d754b374a4d0828aec1ab49d524c5f67ce5
Cr-Commit-Position: refs/heads/master@{#307028}

[Joao da Silva, 2014-12-08 11:10:18]

Belated lgtm