Tentative implementation of string slices (hidden under the flag --string-slices).

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 0bf82863d745e2e12f5c55b23508a24bda0e07c6..921804c98c9d800f29dfa1167ef4935a619eb5a8 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -390,6 +390,10 @@ class StaticMarkingVisitor : public StaticVisitorBase {
                                       ConsString::BodyDescriptor,
                                       void>::Visit);
 
+    table_.Register(kVisitSlicedString,
+                    &FixedBodyVisitor<StaticMarkingVisitor,
+                                      SlicedString::BodyDescriptor,
+                                      void>::Visit);
 
     table_.Register(kVisitFixedArray,
                     &FlexibleBodyVisitor<StaticMarkingVisitor,