Introduce Dart_SetVMFlags API function.

runtime/vm/flags.h

 // Copyright (c) 2011, 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 "vm/assert.h"
 #include "vm/globals.h"
 
@@ skipping 33 matching lines @@
   static int Register_int(int* addr,
                           const char* name,
                           int default_value,
                           const char* comment);
 
   static const char* Register_charp(charp* addr,
                                     const char* name,
                                     const char* default_value,
                                     const char* comment);
 
-  static void ProcessCommandLineFlags(int argc, const char** argv);
+  static bool ProcessCommandLineFlags(int argc, const char** argv);
 
   static Flag* Lookup(const char* name);
 
+  static bool Initialized() { return initialized_; }
+
  private:
   static Flag* flags_;
 
+  static bool initialized_;
+
   static void Parse(const char* option);
 
   // Testing needs direct access to private methods.
   friend void Dart_TestParseFlags();
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Flags);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLAGS_H_