--- old/src/share/vm/gc/g1/concurrentMarkThread.hpp	2017-02-17 20:09:44.545994119 -0500
+++ new/src/share/vm/gc/g1/concurrentMarkThread.hpp	2017-02-17 20:09:44.417987573 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,6 +30,7 @@
 // The Concurrent Mark GC Thread triggers the parallel G1CMConcurrentMarkingTasks
 // as well as handling various marking cleanup.
 
+class ConcurrentGCPhaseManager;
 class G1ConcurrentMark;
 class G1Policy;
 
@@ -50,6 +51,10 @@
 
   volatile State _state;
 
+  // WhiteBox testing support.
+  int _requested_phase;
+  ConcurrentGCPhaseManager* _phase_manager;
+
   void sleepBeforeNextCycle();
   void delay_to_keep_mmu(G1Policy* g1_policy, bool remark);
 
@@ -83,6 +88,11 @@
   // as the CM thread might take some time to wake up before noticing
   // that started() is set and set in_progress().
   bool during_cycle()      { return !idle(); }
+
+  // WhiteBox testing support.
+  bool request_concurrent_phase(const char* phase);
+
+  ConcurrentGCPhaseManager* phase_manager() const { return _phase_manager; }
 };
 
 #endif // SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP