Unify JSEntryStub and JSConstructEntryStub, and some more code stub cleanups.

src/x64/code-stubs-x64.h

Index: src/x64/code-stubs-x64.h
diff --git a/src/x64/code-stubs-x64.h b/src/x64/code-stubs-x64.h
index fd40a284dd2fe37933684d30e3541b3686aafefa..9d34e8570597a60d067089aa72e04c28a1749041 100644
--- a/src/x64/code-stubs-x64.h
+++ b/src/x64/code-stubs-x64.h
@@ -61,8 +61,6 @@ class NameDictionaryLookupStub: public PlatformCodeStub {
                  IndexBits::encode(index.code()) | LookupModeBits::encode(mode);
   }
 
-  void Generate(MacroAssembler* masm);
-
   static void GenerateNegativeLookup(MacroAssembler* masm,
                                      Label* miss,
                                      Label* done,
@@ -111,7 +109,7 @@ class NameDictionaryLookupStub: public PlatformCodeStub {
   class IndexBits: public BitField<int, 8, 4> {};
   class LookupModeBits: public BitField<LookupMode, 12, 1> {};
 
-  DEFINE_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
+  DEFINE_PLATFORM_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
 };
 
 
@@ -319,7 +317,7 @@ class RecordWriteStub: public PlatformCodeStub {
 
   virtual Major MajorKey() const FINAL OVERRIDE { return RecordWrite; }
 
-  void Generate(MacroAssembler* masm);
+  virtual void Generate(MacroAssembler* masm) OVERRIDE;
   void GenerateIncremental(MacroAssembler* masm, Mode mode);
   void CheckNeedsToInformIncrementalMarker(
       MacroAssembler* masm,