Merge bleeding_edge r17376:17693.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 71cd301581fae8c3679c546f3ff4a2834440b365..740cce00476a3ab66ea35fbf48e411f7bbc06da2 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2328,6 +2328,7 @@ bool Isolate::Init(Deserializer* des) {
     InternalArrayConstructorStubBase::InstallDescriptors(this);
     FastNewClosureStub::InstallDescriptors(this);
     NumberToStringStub::InstallDescriptors(this);
+    NewStringAddStub::InstallDescriptors(this);
   }
 
   if (FLAG_sweeper_threads > 0) {
@@ -2465,6 +2466,12 @@ HTracer* Isolate::GetHTracer() {
 }
 
 
+CodeTracer* Isolate::GetCodeTracer() {
+  if (code_tracer() == NULL) set_code_tracer(new CodeTracer(id()));
+  return code_tracer();
+}
+
+
 Map* Isolate::get_initial_js_array_map(ElementsKind kind) {
   Context* native_context = context()->native_context();
   Object* maybe_map_array = native_context->js_array_maps();