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

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index e11dbd786d2dd62638516e6d7cb23c8ec137b4da..7aa2c231efa6ed4a67de79062c776a89d35aa58f 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -605,6 +605,7 @@ bool NormalPageHeap::coalesce()
                 headerAddress += size;
                 continue;
             }
+            header->checkHeader();
             if (startOfGap != headerAddress)
                 addToFreeList(startOfGap, headerAddress - startOfGap);
 
@@ -658,6 +659,7 @@ bool NormalPageHeap::expandObject(HeapObjectHeader* header, size_t newSize)
     // It's possible that Vector requests a smaller expanded size because
     // Vector::shrinkCapacity can set a capacity smaller than the actual payload
     // size.
+    header->checkHeader();
     if (header->payloadSize() >= newSize)
         return true;
     size_t allocationSize = Heap::allocationSizeFromSize(newSize);
@@ -679,6 +681,7 @@ bool NormalPageHeap::expandObject(HeapObjectHeader* header, size_t newSize)
 
 bool NormalPageHeap::shrinkObject(HeapObjectHeader* header, size_t newSize)
 {
+    header->checkHeader();
     ASSERT(header->payloadSize() > newSize);
     size_t allocationSize = Heap::allocationSizeFromSize(newSize);
     ASSERT(header->size() > allocationSize);
@@ -1280,6 +1283,7 @@ static bool isUninitializedMemory(void* objectPointer, size_t objectSize)
 
 static void markPointer(Visitor* visitor, HeapObjectHeader* header)
 {
+    header->checkHeader();
     const GCInfo* gcInfo = Heap::gcInfo(header->gcInfoIndex());
     if (gcInfo->hasVTable() && !vTableInitialized(header->payload())) {
         // We hit this branch when a GC strikes before GarbageCollected<>'s
@@ -1351,6 +1355,7 @@ void NormalPage::snapshot(TracedValue* json, ThreadState::SnapshotInfo* info)
             info->freeSize += header->size();
             continue;
         }
+        header->checkHeader();
 
         size_t tag = info->getClassTag(Heap::gcInfo(header->gcInfoIndex()));
         size_t age = header->age();