Add framework for Dart_Terminate which will cleanup stuff on exit.

runtime/include/dart_api.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 INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 732 matching lines @@
     Dart_IsolateCreateCallback create,
     Dart_IsolateInterruptCallback interrupt,
     Dart_IsolateUnhandledExceptionCallback unhandled_exception,
     Dart_IsolateShutdownCallback shutdown,
     Dart_FileOpenCallback file_open,
     Dart_FileReadCallback file_read,
     Dart_FileWriteCallback file_write,
     Dart_FileCloseCallback file_close);
 
 /**
+ * Cleanup state in the VM before process termination.
+ *
+ * \return True if cleanup is successful.
+ */
+DART_EXPORT bool Dart_Cleanup();
+
+/**
  * Sets command line flags. Should be called before Dart_Initialize.
  *
  * \param argc The length of the arguments array.
  * \param argv An array of arguments.
  *
  * \return True if VM flags set successfully.
  */
 DART_EXPORT bool Dart_SetVMFlags(int argc, const char** argv);
 
 /**
@@ skipping 1518 matching lines @@
  *
  * \param object An object.
  * \param peer A value to store in the peer field.
  *
  * \return Returns an error if 'object' is a subtype of Null, num, or
  *   bool.
  */
 DART_EXPORT Dart_Handle Dart_SetPeer(Dart_Handle object, void* peer);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */