Reapply "Support for precise stepping in functions compiled before debugging was started (step 2)"

src/utils.h

Index: src/utils.h
diff --git a/src/utils.h b/src/utils.h
index a523118a398fac6a982f906451e9c21e1b92dbc1..544b7efdadc05527d07464ef97e77d5a14ce830d 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -143,6 +143,16 @@ static int PointerValueCompare(const T* a, const T* b) {
 }
 
 
+// Compare function to compare the object pointer value of two
+// handlified objects. The handles are passed as pointers to the
+// handles.
+template<typename T> class Handle;  // Forward declaration.
+template <typename T>
+static int HandleObjectPointerCompare(const Handle<T>* a, const Handle<T>* b) {
+  return Compare<T*>(*(*a), *(*b));
+}
+
+
 // Returns the smallest power of two which is >= x. If you pass in a
 // number that is already a power of two, it is returned as is.
 // Implementation is from "Hacker's Delight" by Henry S. Warren, Jr.,