VM restart + shutdown fixes

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 113 matching lines @@
  *
  *   An unhandled exception error provides access to an exception and
  *   stacktrace via the functions Dart_ErrorGetException and
  *   Dart_ErrorGetStacktrace.
  *
  * - Compilation error handles are produced when, during the execution
  *   of Dart code, a compile-time error occurs.  As above, this can
  *   occur in any function which triggers the execution of Dart code.
  *
  * - Fatal error handles are produced when the system wants to shut
- *   down the current isolate.
+ *   down the current isolate. Sometimes a fatal error may be a
+ *   restart request (see Dart_IsRestartRequest). If the embedder does
+ *   not support restarting the VM, then this should be treated as a
+ *   normal fatal error.
  *
  * --- Propagating errors ---
  *
  * When an error handle is returned from the top level invocation of
  * Dart code in a program, the embedder must handle the error as they
  * see fit.  Often, the embedder will print the error message produced
  * by Dart_Error and exit the program.
  *
  * When an error is returned while in the body of a native function,
  * it can be propagated by calling Dart_PropagateError.  Errors should
@@ skipping 116 matching lines @@
  * Is this a fatal error handle?
  *
  * Fatal error handles are produced when the system wants to shut down
  * the current isolate.
  *
  * Requires there to be a current isolate.
  */
 DART_EXPORT bool Dart_IsFatalError(Dart_Handle handle);
 
 /**
+ * Is this error a request to restart the VM?
+ *
+ * If an embedder chooses to support restarting the VM from tools
+ * (such as a debugger), then this function is used to distinguish
+ * restart requests from other fatal errors.
+ *
+ * Requires there to be a current isolate.
+ */
+DART_EXPORT bool Dart_IsVMRestartRequest(Dart_Handle handle);
+
+/**
  * Gets the error message from an error handle.
  *
  * Requires there to be a current isolate.
  *
  * \return A C string containing an error message if the handle is
  *   error. An empty C string ("") if the handle is valid. This C
  *   String is scope allocated and is only valid until the next call
  *   to Dart_ExitScope.
 */
 DART_EXPORT const char* Dart_GetError(Dart_Handle handle);
@@ skipping 2623 matching lines @@
 
 DART_EXPORT Dart_Handle Dart_CreatePrecompiledSnapshot(
     uint8_t** vm_isolate_snapshot_buffer,
     intptr_t* vm_isolate_snapshot_size,
     uint8_t** isolate_snapshot_buffer,
     intptr_t* isolate_snapshot_size,
     uint8_t** instructions_snapshot_buffer,
     intptr_t* instructions_snapshot_size);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */