AllocationSite objects weakly linked for traversal

src/serialize.h

Index: src/serialize.h
diff --git a/src/serialize.h b/src/serialize.h
index a6099afc23f397fdcfedea0781cca8c7767c5ec2..283c1b77a1f5f1297603f12df389fa46635af076 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -347,6 +347,10 @@ class Deserializer: public SerializerDeserializer {
     UNREACHABLE();
   }
 
+  // Allocation sites are present in the snapshot, and must be linked into
+  // a list at deserialization time.
+  void RelinkAllocationSite(AllocationSite* site);
+
   // Fills in some heap data in an area from start to end (non-inclusive).  The
   // space id is used for the write barrier.  The object_address is the address
   // of the object we are writing into, or NULL if we are not writing into an