Turn the NumberToStringStub into a hydrogen stub.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 30ec1c76ca9eda6e355032756c75758e0dfcee1d..a5c2f88b228e85993ffb5271e54cb83026d4254c 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -464,6 +464,25 @@ class ToNumberStub: public HydrogenCodeStub {
 };
 
 
+class NumberToStringStub V8_FINAL : public HydrogenCodeStub {
+ public:
+  NumberToStringStub() {}
+
+  virtual Handle<Code> GenerateCode(Isolate* isolate) V8_OVERRIDE;
+
+  virtual void InitializeInterfaceDescriptor(
+      Isolate* isolate,
+      CodeStubInterfaceDescriptor* descriptor) V8_OVERRIDE;
+
+  // Parameters accessed via CodeStubGraphBuilder::GetParameter()
+  static const int kNumber = 0;
+
+ private:
+  virtual Major MajorKey() V8_OVERRIDE { return NumberToString; }
+  virtual int NotMissMinorKey() V8_OVERRIDE { return 0; }
+};
+
+
 class FastNewClosureStub : public HydrogenCodeStub {
  public:
   explicit FastNewClosureStub(LanguageMode language_mode, bool is_generator)