Oilpan: HeapObjectHeader::checkHeader should not allow access on orphaned pages

Source/platform/heap/HeapAllocator.h

Index: Source/platform/heap/HeapAllocator.h
diff --git a/Source/platform/heap/HeapAllocator.h b/Source/platform/heap/HeapAllocator.h
index 56bdb529f3a79e79945d891eef56bb4627bf7bf4..45ce9f91ed55d922088972cffbd6a7f5f88b8999 100644
--- a/Source/platform/heap/HeapAllocator.h
+++ b/Source/platform/heap/HeapAllocator.h
@@ -277,6 +277,7 @@ void HeapVectorBacking<T, Traits>::finalize(void* pointer)
 
     ASSERT(!WTF::IsTriviallyDestructible<T>::value);
     HeapObjectHeader* header = HeapObjectHeader::fromPayload(pointer);
+    header->checkHeader();
     // Use the payload size as recorded by the heap to determine how many
     // elements to finalize.
     size_t length = header->payloadSize() / sizeof(T);
@@ -310,6 +311,7 @@ void HeapHashTableBacking<Table>::finalize(void* pointer)
     using Value = typename Table::ValueType;
     ASSERT(!WTF::IsTriviallyDestructible<Value>::value);
     HeapObjectHeader* header = HeapObjectHeader::fromPayload(pointer);
+    header->checkHeader();
     // Use the payload size as recorded by the heap to determine how many
     // elements to finalize.
     size_t length = header->payloadSize() / sizeof(Value);