Make accessors for oddball objects return Oddball* instead of Object*.

src/objects.h

Index: src/objects.h
===================================================================
--- src/objects.h	(revision 9511)
+++ src/objects.h	(working copy)
@@ -5216,8 +5216,6 @@
   static const int kHeaderSize = kGlobalReceiverOffset + kPointerSize;
 
  private:
-  friend class AGCCVersionRequiresThisClassToHaveAFriendSoHereItIs;
-
   DISALLOW_IMPLICIT_CONSTRUCTORS(GlobalObject);
 };
 
@@ -7206,7 +7204,6 @@
   static const int kPropertyListOffset = kTagOffset + kPointerSize;
   static const int kHeaderSize         = kPropertyListOffset + kPointerSize;
  protected:
-  friend class AGCCVersionRequiresThisClassToHaveAFriendSoHereItIs;
   DISALLOW_IMPLICIT_CONSTRUCTORS(TemplateInfo);
 };