Add product mode:

runtime/vm/flags.h

 // 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.
 
 #ifndef VM_FLAGS_H_
 #define VM_FLAGS_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 
 typedef const char* charp;
 
 #define DECLARE_FLAG(type, name)                                               \
   extern type FLAG_##name
 
 #define DEFINE_FLAG(type, name, default_value, comment)                        \
   type FLAG_##name = Flags::Register_##type(&FLAG_##name,                      \
                                             #name,                             \
                                             default_value,                     \
                                             comment)
 
+#if defined(PRODUCT)
+#define PRODUCT_FLAG(product_value, type, name, default_value, comment)        \
+  const type FLAG_##name = product_value;
+
+#else  // defined(PRODUCT)
+#define PRODUCT_FLAG(product_value, type, name, default_value, comment)        \
+  type FLAG_##name = Flags::Register_##type(&FLAG_##name,                      \
+                                            #name,                             \
+                                            default_value,                     \
+                                            comment)
+#endif  // defined(PRODUCT)
+
 #define DEFINE_FLAG_HANDLER(handler, name, comment)                            \
   bool DUMMY_##name = Flags::Register_func(handler, #name, comment)
 
 
 #if defined(DEBUG)
 #define DECLARE_DEBUG_FLAG(type, name) DECLARE_FLAG(type, name)
 #define DEFINE_DEBUG_FLAG(type, name, default_value, comment)                  \
   DEFINE_FLAG(type, name, default_value, comment)
 #else
 #define DECLARE_DEBUG_FLAG(type, name)
@@ skipping 71 matching lines @@
   // Testing needs direct access to private methods.
   friend void Dart_TestParseFlags();
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Flags);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLAGS_H_