Add initial hydrogenized NewStringAddStub.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index afa3cd09e90e906746098471fb323501fb40955f..e76bed3c03a5ab36f839eb9e3ec19c745cd4b813 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -682,6 +682,21 @@ Handle<Type> BinaryOpStub::GetResultType(Isolate* isolate) const {
 }
 
 
+void NewStringAddStub::PrintBaseName(StringStream* stream) {
+  stream->Add("NewStringAddStub");
+  if ((flags() & STRING_ADD_CHECK_BOTH) == STRING_ADD_CHECK_BOTH) {
+    stream->Add("_CheckBoth");
+  } else if ((flags() & STRING_ADD_CHECK_LEFT) == STRING_ADD_CHECK_LEFT) {
+    stream->Add("_CheckLeft");
+  } else if ((flags() & STRING_ADD_CHECK_RIGHT) == STRING_ADD_CHECK_RIGHT) {
+    stream->Add("_CheckRight");
+  }
+  if (pretenure_flag() == TENURED) {
+    stream->Add("_Tenured");
+  }
+}
+
+
 InlineCacheState ICCompareStub::GetICState() {
   CompareIC::State state = Max(left_, right_);
   switch (state) {
@@ -1134,6 +1149,13 @@ void FastNewClosureStub::InstallDescriptors(Isolate* isolate) {
 }
 
 
+// static
+void NewStringAddStub::InstallDescriptors(Isolate* isolate) {
+  NewStringAddStub stub(STRING_ADD_CHECK_NONE, NOT_TENURED);
+  InstallDescriptor(isolate, &stub);
+}
+
+
 ArrayConstructorStub::ArrayConstructorStub(Isolate* isolate)
     : argument_count_(ANY) {
   ArrayConstructorStubBase::GenerateStubsAheadOfTime(isolate);