Use source parameter to determine policy priority.

components/policy/core/common/policy_map.cc

 // 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.
 
 #include "components/policy/core/common/policy_map.h"
 
 #include <algorithm>
 
 #include "base/callback.h"
 #include "base/memory/ptr_util.h"
@@ skipping 19 matching lines @@
     copy.value = value->CreateDeepCopy();
   if (external_data_fetcher) {
     copy.external_data_fetcher.reset(
         new ExternalDataFetcher(*external_data_fetcher));
   }
   return copy;
 }
 
 bool PolicyMap::Entry::has_higher_priority_than(
     const PolicyMap::Entry& other) const {
-  if (level == other.level)
+  if (level == other.level) {
+    if (scope == other.scope) {
+      return source > other.source;
+    }
     return scope > other.scope;
-  else
-    return level > other.level;
+  }
+  return level > other.level;
 }
 
 bool PolicyMap::Entry::Equals(const PolicyMap::Entry& other) const {
   return level == other.level && scope == other.scope &&
          source == other.source &&  // Necessary for PolicyUIHandler observers.
                                     // They have to update when sources change.
          base::Value::Equals(value.get(), other.value.get()) &&
          ExternalDataFetcher::Equals(external_data_fetcher.get(),
                                      other.external_data_fetcher.get());
 }
@@ skipping 156 matching lines @@
   while (iter != map_.end()) {
     if (filter.Run(iter) == deletion_value) {
       map_.erase(iter++);
     } else {
       ++iter;
     }
   }
 }
 
 }  // namespace policy