Replace OStream with std::ostream.

src/hydrogen-types.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef HYDROGEN_TYPES_H_
 #define HYDROGEN_TYPES_H_
 
 #include <climits>
+#include <iosfwd>
 
 #include "src/base/macros.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 template <typename T> class Handle;
 class Object;
-class OStream;
 
 #define HTYPE_LIST(V)                                 \
   V(Any, 0x0)              /* 0000 0000 0000 0000 */  \
   V(Tagged, 0x1)           /* 0000 0000 0000 0001 */  \
   V(TaggedPrimitive, 0x5)  /* 0000 0000 0000 0101 */  \
   V(TaggedNumber, 0xd)     /* 0000 0000 0000 1101 */  \
   V(Smi, 0x1d)             /* 0000 0000 0001 1101 */  \
   V(HeapObject, 0x21)      /* 0000 0000 0010 0001 */  \
   V(HeapPrimitive, 0x25)   /* 0000 0000 0010 0101 */  \
   V(Null, 0x27)            /* 0000 0000 0010 0111 */  \
@@ skipping 29 matching lines @@
     bool Is##Name() const WARN_UNUSED_RESULT {   \
       return IsSubtypeOf(HType::Name());            \
     }
   HTYPE_LIST(DECLARE_IS_TYPE)
   #undef DECLARE_IS_TYPE
 
   template <class T>
   static HType FromType(typename T::TypeHandle type) WARN_UNUSED_RESULT;
   static HType FromValue(Handle<Object> value) WARN_UNUSED_RESULT;
 
-  friend OStream& operator<<(OStream& os, const HType& t);
+  friend std::ostream& operator<<(std::ostream& os, const HType& t);
 
  private:
   enum Kind {
     #define DECLARE_TYPE(Name, mask) k##Name = mask,
     HTYPE_LIST(DECLARE_TYPE)
     #undef DECLARE_TYPE
     LAST_KIND = kNone
   };
 
   // Make sure type fits in int16.
   STATIC_ASSERT(LAST_KIND < (1 << (CHAR_BIT * sizeof(int16_t))));
 
   explicit HType(Kind kind) : kind_(kind) { }
 
   int16_t kind_;
 };
 
 
-OStream& operator<<(OStream& os, const HType& t);
+std::ostream& operator<<(std::ostream& os, const HType& t);
 } }  // namespace v8::internal
 
 #endif  // HYDROGEN_TYPES_H_