Flag for serialization when compiling code stubs if --serialize-toplevel.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index ed0310e37d6db2f0d1197b8687dcc8327f17d5f2..efbd40c42467e86a13f8a1005e9c6a3c8d5411c2 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -149,6 +149,9 @@ Handle<Code> PlatformCodeStub::GenerateCode() {
   // Generate the new code.
   MacroAssembler masm(isolate(), NULL, 256);
 
+  // TODO(yangguo) remove this once the code serializer handles code stubs.
+  if (FLAG_serialize_toplevel) masm.enable_serializer();
+
   {
     // Update the static counter each time a new code stub is generated.
     isolate()->counters()->code_stubs()->Increment();