Refactor the Heap into ThreadHeap to prepare for per thread heaps

third_party/WebKit/Source/platform/heap/SafePoint.h

 // Copyright 2015 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.
 
 #ifndef SafePoint_h
 #define SafePoint_h
 
 #include "platform/heap/ThreadState.h"
 #include "wtf/ThreadingPrimitives.h"
 
@@ skipping 75 matching lines @@
     }
 
     MutexBase& m_mutex;
     bool m_locked;
 };
 
 class SafePointBarrier final {
     USING_FAST_MALLOC(SafePointBarrier);
     WTF_MAKE_NONCOPYABLE(SafePointBarrier);
 public:
-    SafePointBarrier();
+    explicit SafePointBarrier(Heap*);
     ~SafePointBarrier();
 
     // Request other attached threads that are not at safe points to park
     // themselves on safepoints.
     bool parkOthers();
 
     // Resume executions of other attached threads that are parked at
     // the safe points.
     void resumeOthers(bool barrierLocked = false);
 
@@ skipping 14 matching lines @@
     static void enterSafePointAfterPushRegisters(SafePointBarrier* barrier, ThreadState* state, intptr_t* stackEnd)
     {
         barrier->doEnterSafePoint(state, stackEnd);
     }
 
     volatile int m_canResume;
     volatile int m_unparkedThreadCount;
     Mutex m_mutex;
     ThreadCondition m_parked;
     ThreadCondition m_resume;
+    Heap* m_heap;
 };
 
 } // namespace blink
 
 #endif