Replace OStream with std::ostream.

src/compiler/representation-change.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 V8_COMPILER_REPRESENTATION_CHANGE_H_
 #define V8_COMPILER_REPRESENTATION_CHANGE_H_
 
+#include <sstream>
+
 #include "src/base/bits.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/simplified-operator.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 374 matching lines @@
 
   friend class RepresentationChangerTester;  // accesses the below fields.
 
   bool testing_type_errors_;  // If {true}, don't abort on a type error.
   bool type_error_;           // Set when a type error is detected.
 
   Node* TypeError(Node* node, MachineTypeUnion output_type,
                   MachineTypeUnion use) {
     type_error_ = true;
     if (!testing_type_errors_) {
-      OStringStream out_str;
+      std::ostringstream out_str;
       out_str << static_cast<MachineType>(output_type);
 
-      OStringStream use_str;
+      std::ostringstream use_str;
       use_str << static_cast<MachineType>(use);
 
       V8_Fatal(__FILE__, __LINE__,
                "RepresentationChangerError: node #%d:%s of "
                "%s cannot be changed to %s",
-               node->id(), node->op()->mnemonic(), out_str.c_str(),
-               use_str.c_str());
+               node->id(), node->op()->mnemonic(), out_str.str().c_str(),
+               use_str.str().c_str());
     }
     return node;
   }
 
   Node* InsertChangeFloat32ToFloat64(Node* node) {
     return jsgraph()->graph()->NewNode(machine()->ChangeFloat32ToFloat64(),
                                        node);
   }
 
   JSGraph* jsgraph() { return jsgraph_; }
   Isolate* isolate() { return isolate_; }
   SimplifiedOperatorBuilder* simplified() { return simplified_; }
   MachineOperatorBuilder* machine() { return jsgraph()->machine(); }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_REPRESENTATION_CHANGE_H_