Remove orphaned pages from Oilpan

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

 // Copyright 2017 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 VisitorImpl_h
 #define VisitorImpl_h
 
 #include "platform/heap/Heap.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/heap/Visitor.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 inline void Visitor::markHeader(HeapObjectHeader* header,
                                 const void* objectPointer,
                                 TraceCallback callback) {
   DCHECK(header);
   DCHECK(objectPointer);
 
-  // If you hit this DCHECK, it means that there is a dangling pointer
-  // from a live thread heap to a dead thread heap.  We must eliminate
-  // the dangling pointer.
-  // Release builds don't have the DCHECK, but it is OK because
-  // release builds will crash in the following header->isMarked()
-  // because all the entries of the orphaned arenas are zapped.
-  DCHECK(!pageFromObject(objectPointer)->orphaned());
-
   if (header->isMarked())
     return;
 
   DCHECK(ThreadState::current()->isInGC());
   DCHECK(getMarkingMode() != VisitorMarkingMode::WeakProcessing);
 
   // A GC should only mark the objects that belong in its heap.
   DCHECK(&pageFromObject(objectPointer)->arena()->getThreadState()->heap() ==
          &heap());
 
@@ skipping 89 matching lines @@
                                                   void* callbackData) {
   if (getMarkingMode() != VisitorMarkingMode::GlobalMarkingWithCompaction)
     return;
   heap().registerMovingObjectCallback(
       reinterpret_cast<MovableReference>(backingStore), callback, callbackData);
 }
 
 }  // namespace blink
 
 #endif