Merge flush code phase into marking phase.

src/mark-compact.h

Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index ad635867c396dbe0759de49138deeeb779ff2ada..a5fd8d31d4e98e2ad4f4d0f36751d376d1d2857b 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -175,6 +175,10 @@ class MarkCompactCollector: public AllStatic {
   friend class RootMarkingVisitor;
   friend class MarkingVisitor;
   friend class StaticMarkingVisitor;
+  friend class CodeMarkingVisitor;
+  friend class SharedFunctionInfoMarkingVisitor;
+
+  static void PrepareForCodeFlushing();
 
   // Marking operations for objects reachable from roots.
   static void MarkLiveObjects();