Introduce ThreadState::isOnThreadHeap() helper predicate.

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 555 matching lines @@
       DCHECK(!state->sweepForbidden());
       DCHECK(!state->m_orderedPreFinalizers.contains(
           PreFinalizer(self, T::invokePreFinalizer)));
       state->m_orderedPreFinalizers.add(
           PreFinalizer(self, T::invokePreFinalizer));
     }
   };
 
   static const char* gcReasonString(BlinkGC::GCReason);
 
+  // Returns |true| if |object| resides on this thread's heap.
+  // It is well-defined to call this method on any heap allocated
+  // reference, provided its associated heap hasn't been detached
+  // and shut down. Its behavior is undefined for any other pointer
+  // value.
+  bool isOnThreadHeap(const void* object) const {
+    return &fromObject(object)->heap() == &heap();
+  }
+
  private:
   template <typename T>
   friend class PrefinalizerRegistration;
   enum SnapshotType { HeapSnapshot, FreelistSnapshot };
 
   explicit ThreadState(BlinkGC::ThreadHeapMode);
   ~ThreadState();
 
   NO_SANITIZE_ADDRESS void copyStackUntilSafePointScope();
   void clearSafePointScopeMarker() {
@@ skipping 179 matching lines @@
 class ThreadStateFor<AnyThread> {
   STATIC_ONLY(ThreadStateFor);
 
  public:
   static ThreadState* state() { return ThreadState::current(); }
 };
 
 }  // namespace blink
 
 #endif  // ThreadState_h