Oilpan: insist on eager sweeping for some objects.

Source/platform/heap/Heap.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 1101 matching lines @@
             if (size < 32)
                 return NormalPage1HeapIndex;
             return NormalPage2HeapIndex;
         }
         if (size < 128)
             return NormalPage3HeapIndex;
         return NormalPage4HeapIndex;
     }
 };
 
-#define EAGERLY_SWEEP(TYPE)                 \
-template<typename T>                        \
-class HeapIndexTrait<T, typename WTF::EnableIf<WTF::IsSubclass<T, TYPE>::value>::Type> { \
-public:                                     \
-    static int heapIndexForObject(size_t)   \
-    {                                       \
-        return EagerSweepHeapIndex;         \
-    }                                       \
-}
+// TODO(Oilpan): enable this macro when enabling lazy sweeping, non-Oilpan.
+#if ENABLE(OILPAN)
+#define EAGERLY_SWEEP() typedef int IsEagerlySweptMarker
+#else
+#define EAGERLY_SWEEP()
+#endif
+
+template<typename T>
+struct IsEagerlySweptType {
+private:
+    typedef char YesType;
+    struct NoType {
+        char padding[8];
+    };
+
+    template <typename U> static YesType checkMarker(typename U::IsEagerlySweptMarker*);
+    template <typename U> static NoType checkMarker(...);
+
+public:
+    static const bool value = sizeof(checkMarker<T>(nullptr)) == sizeof(YesType);
+};
+
+template<typename T>
+class HeapIndexTrait<T, typename WTF::EnableIf<IsEagerlySweptType<T>::value>::Type> {
+public:
+    static int heapIndexForObject(size_t)
+    {
+        return EagerSweepHeapIndex;
+    }
+};
 
 NO_SANITIZE_ADDRESS inline
 size_t HeapObjectHeader::size() const
 {
     size_t result = m_encoded & headerSizeMask;
     // Large objects should not refer to header->size().
     // The actual size of a large object is stored in
     // LargeObjectPage::m_payloadSize.
     ASSERT(result != largeObjectSizeInHeader);
     ASSERT(!pageFromObject(this)->isLargeObjectPage());
@@ skipping 132 matching lines @@
     size_t copySize = previousHeader->payloadSize();
     if (copySize > size)
         copySize = size;
     memcpy(address, previous, copySize);
     return address;
 }
 
 } // namespace blink
 
 #endif // Heap_h