Added SchemaMap::GetChanges().

components/policy/core/common/policy_namespace.h

Index: components/policy/core/common/policy_namespace.h
diff --git a/components/policy/core/common/policy_namespace.h b/components/policy/core/common/policy_namespace.h
index 4d8cf1cc0f78ff79b12578a2ef69ea7ca5ba00e5..86dc5866afc5f7b207080626ebd3c636fc401175 100644
--- a/components/policy/core/common/policy_namespace.h
+++ b/components/policy/core/common/policy_namespace.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_POLICY_CORE_COMMON_POLICY_NAMESPACE_H_
 
 #include <string>
+#include <vector>
 
 #include "components/policy/policy_export.h"
 
@@ -44,6 +45,8 @@ struct POLICY_EXPORT PolicyNamespace {
   std::string component_id;
 };
 
+typedef std::vector<PolicyNamespace> PolicyNamespaceList;
+
 }  // namespace policy
 
 #endif  // COMPONENTS_POLICY_CORE_COMMON_POLICY_NAMESPACE_H_