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

src/handles.h

Index: src/handles.h
diff --git a/src/handles.h b/src/handles.h
index 13c6dd67f71e4aca1c7b59e6057f143a29347fd3..091019a01d7bb4779b8a398161e27fa0c6cff8f9 100644
--- a/src/handles.h
+++ b/src/handles.h
@@ -186,6 +186,16 @@ void FlattenString(Handle<String> str);
 // string.
 Handle<String> FlattenGetString(Handle<String> str);
 
+// Truncates a (sliced) string.
+void TruncateString(Handle<String> str);
+
+// Truncates a (sliced) string and returns the underlying sequential string.
+Handle<String> TruncateGetString(Handle<String> str);
+
+// Flattens a cons string or truncates a sliced string, which ever fits.
+void FlattenOrTruncateString(Handle<String> str);
+
+
 Handle<Object> SetProperty(Handle<JSReceiver> object,
                            Handle<String> key,
                            Handle<Object> value,