[Offline pages] Add a builder and feature struct to policy

components/offline_pages/client_policy_controller.h

Index: components/offline_pages/client_policy_controller.h
diff --git a/components/offline_pages/client_policy_controller.h b/components/offline_pages/client_policy_controller.h
index 231d028d4a6e3bf0e79ce41e35efee983c47bce5..92c4b2aaad726a4688e26ca6584c2e180aab03cb 100644
--- a/components/offline_pages/client_policy_controller.h
+++ b/components/offline_pages/client_policy_controller.h
@@ -33,6 +33,12 @@ class ClientPolicyController {
   // Get the client policy for |name_space|.
   const OfflinePageClientPolicy& GetPolicy(const std::string& name_space) const;
 
+  // Returns whether the policy for |name_space| is user requested.
+  bool IsUserRequested(const std::string& name_space) const;

[Dmitry Titov, 2016/09/01 00:06:12]

Naming - it is not "user requested" that we actually do here. If it is to
replace the code in cache clearing feature, the better name woudl eb
specifically about what is going on there: "IsRemovedOnChromeCachesReset()" for
example.

[chili, 2016/09/06 20:55:20]

Done.

+
+  // Returns whether the policy for |name_space| is downloaded.

[dewittj, 2016/09/12 18:06:35]

This is worded strangely, does it mean that it should be shown in the download
home?

[chili, 2016/09/12 21:24:06]

Please see latest upload.  I think it clears this up?

+  bool IsDownloaded(const std::string& name_space) const;

[Dmitry Titov, 2016/09/01 00:06:12]

Naming - if this is to replace the filter in DownloadUIAdapter::IsVisibleInUI,
then perhaps better name would be "IsVisibleInDownloadHomeUI()".

It is good to have those to be long and descriptive, since we want to avoid
situations when different but similar-looking characteristics are lumped
together, or when inspection of call sites is necessary to understand what these
bits are enabling/disabling.

[chili, 2016/09/06 20:55:20]

How does 'IsSupportedByDownload' sound?  While I think it's good to have
descriptive names, I also want to avoid being so specific that it becomes
necessary to have 2 or more of the same methods that do the exact same thing...

This is also taken from offline pages suggestions under ntp
(https://cs.chromium.org/chromium/src/components/ntp_snippets/offline_pages/of...)
which I think is out of date based on the comments there

+
  private:
   // The map from name_space to a client policy. Will be generated
   // as pre-defined values for now.