Turn ToNumberStub into a hydrogen code stub.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 33593544d68beb8b1ef825631e466dded7b63866..bc581d837d42ae13ffb754d1dc349a6ceb124cd7 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -474,15 +474,19 @@ class InterruptStub : public PlatformCodeStub {
 };
 
 
-class ToNumberStub: public PlatformCodeStub {
+class ToNumberStub: public HydrogenCodeStub {
  public:
   ToNumberStub() { }
 
-  void Generate(MacroAssembler* masm);
+  virtual Handle<Code> GenerateCode();
+
+  virtual void InitializeInterfaceDescriptor(
+      Isolate* isolate,
+      CodeStubInterfaceDescriptor* descriptor);
 
  private:
   Major MajorKey() { return ToNumber; }
-  int MinorKey() { return 0; }
+  int NotMissMinorKey() { return 0; }
 };