LiveEdit: calculate a real script difference

src/handles.h

Index: src/handles.h
diff --git a/src/handles.h b/src/handles.h
index 54c3b45f757fd7b778ee61547a0d33b429c313fa..5baceee3367940788d138d492515aad911f0f4c8 100644
--- a/src/handles.h
+++ b/src/handles.h
@@ -271,6 +271,11 @@ Handle<JSValue> GetScriptWrapper(Handle<Script> script);
 
 // Script line number computations.
 void InitScriptLineEnds(Handle<Script> script);
+// For string calculates an array of line end positions. If the string
+// does not end with a new line character, this character may optionally be
+// imagined.
+Handle<FixedArray> CalculateLineEnds(Handle<String> string,
+                                     bool with_imaginary_last_new_line);
 int GetScriptLineNumber(Handle<Script> script, int code_position);
 // The safe version does not make heap allocations but may work much slower.
 int GetScriptLineNumberSafe(Handle<Script> script, int code_position);