Remove new space allocation in optimizing compiler, use Symbols::FromConcat where appropriate

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 7136 matching lines @@
   return "RedirectionData class";
 }
 
 
 void RedirectionData::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Object::PrintJSONImpl(stream, ref);
 }
 
 
 RawString* Field::GetterName(const String& field_name) {
-  return String::Concat(Symbols::GetterPrefix(), field_name);
+  return Field::GetterSymbol(field_name);
 }
 
 
 RawString* Field::GetterSymbol(const String& field_name) {
   return Symbols::FromConcat(Symbols::GetterPrefix(), field_name);
 }
 
 
 RawString* Field::SetterName(const String& field_name) {
   return String::Concat(Symbols::SetterPrefix(), field_name);
@@ skipping 14247 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart