Make HeapObjectHeader::checkHeader private.

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

Index: third_party/WebKit/Source/platform/heap/HeapAllocator.h
diff --git a/third_party/WebKit/Source/platform/heap/HeapAllocator.h b/third_party/WebKit/Source/platform/heap/HeapAllocator.h
index 0e7553280ab70aa40d94aa435d0fe6702aad2a38..d224550feae0613b68a0905a982a1bffd74bfe03 100644
--- a/third_party/WebKit/Source/platform/heap/HeapAllocator.h
+++ b/third_party/WebKit/Source/platform/heap/HeapAllocator.h
@@ -313,7 +313,6 @@ 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);
@@ -342,7 +341,6 @@ 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);