Turn FastNewContextStub into a HydrogenCodeStub.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index df39b5cf2fbd8ee207bc271e1730e56050399eb1..8fb74b5c1b9e80406a6f424baa91c39dd1e53925 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -556,7 +556,7 @@ class FastNewClosureStub : public HydrogenCodeStub {
 };
 
 
-class FastNewContextStub : public PlatformCodeStub {
+class FastNewContextStub V8_FINAL : public HydrogenCodeStub {
  public:
   static const int kMaximumSlots = 64;
 
@@ -564,13 +564,24 @@ class FastNewContextStub : public PlatformCodeStub {
     ASSERT(slots_ > 0 && slots_ <= kMaximumSlots);
   }
 
-  void Generate(MacroAssembler* masm);
+  virtual Handle<Code> GenerateCode(Isolate* isolate);
+
+  virtual void InitializeInterfaceDescriptor(
+      Isolate* isolate,
+      CodeStubInterfaceDescriptor* descriptor);
+
+  static void InstallDescriptors(Isolate* isolate);
+
+  int slots() const { return slots_; }
+
+  virtual Major MajorKey() V8_OVERRIDE { return FastNewContext; }
+  virtual int NotMissMinorKey() V8_OVERRIDE { return slots_; }
+
+  // Parameters accessed via CodeStubGraphBuilder::GetParameter()
+  static const int kFunction = 0;
 
  private:
   int slots_;
-
-  Major MajorKey() { return FastNewContext; }
-  int MinorKey() { return slots_; }
 };