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

components/policy/core/common/policy_map.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_POLICY_CORE_COMMON_POLICY_MAP_H_
 #define COMPONENTS_POLICY_CORE_COMMON_POLICY_MAP_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 10 matching lines @@
 class POLICY_EXPORT PolicyMap {
  public:
   // Each policy maps to an Entry which keeps the policy value as well as other
   // relevant data about the policy.
   struct POLICY_EXPORT Entry {
     PolicyLevel level;
     PolicyScope scope;
     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|.
     void DeleteOwnedMembers();
 
     // Returns a copy of |this|.
     scoped_ptr<Entry> DeepCopy() const;
 
     // Returns true if |this| has higher priority than |other|.
     bool has_higher_priority_than(const Entry& other) const;
@@ skipping 10 matching lines @@
 
   // Returns a weak reference to the entry currently stored for key |policy|,
   // or NULL if not found. Ownership is retained by the PolicyMap.
   const Entry* Get(const std::string& policy) const;
 
   // Returns a weak reference to the value currently stored for key |policy|,
   // or NULL if not found. Ownership is retained by the 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);
 
   // Swaps the internal representation of |this| with |other|.
   void Swap(PolicyMap* other);
 
   // |this| becomes a copy of |other|. Any existing policies are dropped.
   void CopyFrom(const PolicyMap& other);
 
   // Returns a copy of |this|.
@@ skipping 39 matching lines @@
                              const PolicyMapType::value_type& b);
 
   PolicyMapType map_;
 
   DISALLOW_COPY_AND_ASSIGN(PolicyMap);
 };
 
 }  // namespace policy
 
 #endif  // COMPONENTS_POLICY_CORE_COMMON_POLICY_MAP_H_