A64: Synchronize with r17635.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 9ea0c49fe55994b33b51245d5db03155041458a3..a202eb3c64d44301b058969de3883caabe52bfcf 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2329,6 +2329,7 @@ bool Isolate::Init(Deserializer* des) {
     InternalArrayConstructorStubBase::InstallDescriptors(this);
     FastNewClosureStub::InstallDescriptors(this);
     NumberToStringStub::InstallDescriptors(this);
+    NewStringAddStub::InstallDescriptors(this);
   }
 
   if (FLAG_sweeper_threads > 0) {
@@ -2466,6 +2467,12 @@ 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();