Use enum for per thread heap enabled flag

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 156 matching lines @@
             ASSERT(m_state->m_sweepForbidden);
             m_state->m_sweepForbidden = false;
         }
     private:
         ThreadState* m_state;
     };
 
     void lockThreadAttachMutex();
     void unlockThreadAttachMutex();
 
-    bool perThreadHeapEnabled() const { return m_perThreadHeapEnabled; }
+    BlinkGC::ThreadHeapMode threadHeapMode() const { return m_threadHeapMode; }
 
     bool isTerminating() { return m_isTerminating; }
 
     static void attachMainThread();
     static void detachMainThread();
     void cleanupMainThread();
 
     // Associate ThreadState object with the current thread. After this
     // call thread can start using the garbage collected heap infrastructure.
     // It also has to periodically check for safepoints.
-    static void attachCurrentThread(bool perThreadHeapEnabled);
+    static void attachCurrentThread(BlinkGC::ThreadHeapMode);
 
     // Disassociate attached ThreadState from the current thread. The thread
     // can no longer use the garbage collected heap after this call.
     static void detachCurrentThread();
 
     static ThreadState* current()
     {
 #if defined(__GLIBC__) || OS(ANDROID) || OS(FREEBSD)
         // TLS lookup is fast in these platforms.
         return **s_threadSpecific;
@@ skipping 334 matching lines @@
     void collectGarbage(BlinkGC::StackState, BlinkGC::GCType, BlinkGC::GCReason);
     void collectGarbageForTerminatingThread();
     void collectAllGarbage();
 
 private:
     enum SnapshotType {
         HeapSnapshot,
         FreelistSnapshot
     };
 
-    ThreadState(bool perThreadHeapEnabled);
+    explicit ThreadState(BlinkGC::ThreadHeapMode);
     ~ThreadState();
 
     NO_SANITIZE_ADDRESS void copyStackUntilSafePointScope();
     void clearSafePointScopeMarker()
     {
         m_safePointStackCopy.clear();
         m_safePointScopeMarker = nullptr;
     }
 
     // shouldSchedule{Precise,Idle}GC and shouldForceConservativeGC
@@ skipping 89 matching lines @@
     bool m_sweepForbidden;
     size_t m_noAllocationCount;
     size_t m_gcForbiddenCount;
     double m_accumulatedSweepingTime;
 
     BaseArena* m_arenas[BlinkGC::NumberOfArenas];
     int m_vectorBackingArenaIndex;
     size_t m_arenaAges[BlinkGC::NumberOfArenas];
     size_t m_currentArenaAges;
 
-    bool m_perThreadHeapEnabled;
+    const BlinkGC::ThreadHeapMode m_threadHeapMode;
     bool m_isTerminating;
     GarbageCollectedMixinConstructorMarker* m_gcMixinMarker;
 
     bool m_shouldFlushHeapDoesNotContainCache;
     GCState m_gcState;
 
     std::unique_ptr<CallbackStack> m_threadLocalWeakCallbackStack;
 
     // Pre-finalizers are called in the reverse order in which they are
     // registered by the constructors (including constructors of Mixin objects)
@@ skipping 49 matching lines @@
 
 template<> class ThreadStateFor<AnyThread> {
     STATIC_ONLY(ThreadStateFor);
 public:
     static ThreadState* state() { return ThreadState::current(); }
 };
 
 } // namespace blink
 
 #endif // ThreadState_h