Add source column to chrome://policy showing the origins of policies.

components/policy/core/common/policy_map.h

Index: components/policy/core/common/policy_map.h
diff --git a/components/policy/core/common/policy_map.h b/components/policy/core/common/policy_map.h
index 7d0d06b80b4ba35e13154726b2dabd17d7e86a43..c7059afec08b19f76c95a45a2c331354c6ef21d3 100644
--- a/components/policy/core/common/policy_map.h
+++ b/components/policy/core/common/policy_map.h
@@ -28,6 +28,9 @@ class POLICY_EXPORT PolicyMap {
     base::Value* value;
     ExternalDataFetcher* external_data_fetcher;
 
+    // For debugging and displaying only. Set by provider delivering the policy.
+    PolicySource source;
+
     Entry();
 
     // Deletes all members owned by |this|.
@@ -58,14 +61,25 @@ class POLICY_EXPORT PolicyMap {
   // This is equivalent to Get(policy)->value, when it doesn't return NULL.
   const base::Value* GetValue(const std::string& policy) const;
 
-  // Takes ownership of |value| and |external_data_fetcher|. Overwrites any
-  // existing information stored in the map for the key |policy|.
+  // Sets the source of every Entry with unknown source to the passed |source|.

[bartfab (slow), 2015/09/14 14:42:27]

Nit: s/passed/given/ ("passed" is used with scoped_ptrs only).

[fhorschig, 2015/09/16 13:52:05]

Done.

+  void ApplySourceToEntries(PolicySource source);
+
+  // Calls |SetWithSource| with default source.

[bartfab (slow), 2015/09/14 14:42:27]

Nit 1: The most common style is to use |pipes| for variables, constants and
classes but empty brackets() instead for methods.
Nit 2: What is the default policy source?
Nit 3: Retain the documentation that this takes ownership of |value| and
|external_data_fetcher| (it is easy to miss if the comment is attached to the
method below only). Of course it would be even better if we used scoped_ptrs
here.

[fhorschig, 2015/09/16 13:52:05]

1 & 2 Done. Nit 3: This change is certainly useful but should get an own issue.

   void Set(const std::string& policy,

[bartfab (slow), 2015/09/14 14:42:27]

Would it not be possible to make the code that calls Set() aware of the policy
source? That code already provides the |level| and |scope|. If it also set the
|source|, we could do away with the separate SetWithSource() method and with
ApplySourcesToEntries().

[fhorschig, 2015/09/16 13:52:05]

It is possible. Let me just update these 531 references. 

[bartfab (slow), 2015/09/16 15:58:40]

Thanks. This looks much better now.

[fhorschig, 2015/09/17 11:20:41]

Thank you :D

            PolicyLevel level,
            PolicyScope scope,
            base::Value* value,
            ExternalDataFetcher* external_data_fetcher);
 
+  // Takes ownership of |value| and |external_data_fetcher|. Overwrites any
+  // existing information stored in the map for the key |policy|.
+  void SetWithSource(const std::string& policy,
+           PolicyLevel level,
+           PolicyScope scope,
+           base::Value* value,
+           ExternalDataFetcher* external_data_fetcher,
+           PolicySource source);
+
   // Erase the given |policy|, if it exists in this map.
   void Erase(const std::string& policy);