Small efficiency fix.

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 "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
 #include "vm/bootstrap.h"
@@ skipping 4129 matching lines @@
 
 RawString* Field::SetterSymbol(const String& field_name) {
   String& str = String::Handle();
   str = Field::SetterName(field_name);
   return String::NewSymbol(str);
 }
 
 
 RawString* Field::NameFromGetter(const String& getter_name) {
   String& str = String::Handle();
-  str = String::New(kGetterPrefix);
-  str = String::SubString(getter_name, str.Length());
+  str = String::SubString(getter_name, strlen(kGetterPrefix));
   return str.raw();
 }
 
 
 RawString* Field::NameFromSetter(const String& setter_name) {
   String& str = String::Handle();
-  str = String::New(kSetterPrefix);
-  str = String::SubString(setter_name, str.Length());
+  str = String::SubString(setter_name, strlen(kSetterPrefix));
   return str.raw();
 }
 
 
 void Field::set_name(const String& value) const {
   ASSERT(value.IsSymbol());
   StorePointer(&raw_ptr()->name_, value.raw());
 }
 
 
@@ skipping 5930 matching lines @@
   const String& str = String::Handle(pattern());
   const char* format = "JSRegExp: pattern=%s flags=%s";
   intptr_t len = OS::SNPrint(NULL, 0, format, str.ToCString(), Flags());
   char* chars = reinterpret_cast<char*>(
       Isolate::Current()->current_zone()->Allocate(len + 1));
   OS::SNPrint(chars, (len + 1), format, str.ToCString(), Flags());
   return chars;
 }
 
 }  // namespace dart