Add test coverage for setting up initial iptables rules.

Bug: 28362720
Test: bullhead builds, boots
Test: netd_{unit,integration}_test pass
Change-Id: I2ab9269d9bca3a7b8b168b801360d3fdb6119f05
diff --git a/server/Controllers.h b/server/Controllers.h
index 0bfa0e7..0754932 100644
--- a/server/Controllers.h
+++ b/server/Controllers.h
@@ -60,7 +60,13 @@
     void init();
 
 private:
+    friend class ControllersTest;
     void initIptablesRules();
+    static void initChildChains();
+    static void createChildChains(IptablesTarget target, const char* table, const char* parentChain,
+                                  const char** childChains, bool exclusive);
+    static int (*execIptablesSilently)(IptablesTarget target, ...);
+    static int (*execIptablesRestore)(IptablesTarget, const std::string&);
 };
 
 extern Controllers* gCtls;