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..8ff480a71c2102652b2692f18d66943f20adaf93 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|.
@@ -63,6 +66,7 @@ class POLICY_EXPORT PolicyMap {
   void Set(const std::string& policy,
            PolicyLevel level,
            PolicyScope scope,
+           PolicySource source,
            base::Value* value,
            ExternalDataFetcher* external_data_fetcher);
 
@@ -85,11 +89,12 @@ class POLICY_EXPORT PolicyMap {
   void MergeFrom(const PolicyMap& other);
 
   // Loads the values in |policies| into this PolicyMap. All policies loaded
-  // will have |level| and |scope| in their entries. Existing entries are
-  // replaced.
+  // will have |level|, |scope| and |source| in their entries. Existing entries
+  // are replaced.
   void LoadFrom(const base::DictionaryValue* policies,
                 PolicyLevel level,
-                PolicyScope scope);
+                PolicyScope scope,
+                PolicySource source);
 
   // Compares this value map against |other| and stores all key names that have
   // different values or reference different external data in |differing_keys|.