Provide baseline for experimental GC implementation.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 06b3ee46890881d5ef82d18a232799ec955fae0b..c0063037cce33f2dcc96954f62e6cfc4c12b3cfa 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1252,13 +1252,11 @@ class Heap : public AllStatic {
   // Support for computing object sizes during GC.
   static HeapObjectCallback gc_safe_size_of_old_object_;
   static int GcSafeSizeOfOldObject(HeapObject* object);
-  static int GcSafeSizeOfOldObjectWithEncodedMap(HeapObject* object);
 
   // Update the GC state. Called from the mark-compact collector.
   static void MarkMapPointersAsEncoded(bool encoded) {
-    gc_safe_size_of_old_object_ = encoded
-        ? &GcSafeSizeOfOldObjectWithEncodedMap
-        : &GcSafeSizeOfOldObject;
+    ASSERT(!encoded);
+    gc_safe_size_of_old_object_ = &GcSafeSizeOfOldObject;
   }
 
   // Checks whether a global GC is necessary
@@ -1496,6 +1494,7 @@ class VerifyPointersVisitor: public ObjectVisitor {
 };
 
 
+#ifdef ENABLE_CARDMARKING_WRITE_BARRIER
 // Visitor class to verify interior pointers in spaces that use region marks
 // to keep track of intergenerational references.
 // As VerifyPointersVisitor but also checks that dirty marks are set
@@ -1518,6 +1517,7 @@ class VerifyPointersAndDirtyRegionsVisitor: public ObjectVisitor {
   }
 };
 #endif
+#endif
 
 
 // Space iterator for iterating over all spaces of the heap.