Improve error handling in the process library.

runtime/bin/process.dart

 // 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.
 
 interface Process factory _Process {
   /*
    * Creates a new process object preparing to run the executable
-   * found at [path] with the specified [arguments].  [arguments] has
-   * to be a const string array, c.f. bug 5314640.
+   * found at [path] with the specified [arguments].
    */
   Process(String path, List<String> arguments);
 
   /*
    * Start the process by running the specified executable. An
    * exception of type [ProcessException] is thrown if the process
    * cannot be started. There is a remote possibility of an exception
    * being thrown even though the child process did actually start.
    */
   void start();
@@ skipping 37 matching lines @@
   /*
    * Contains the system message for the process exception if any.
    */
   final String message;
 
   /*
    * Contains the OS error code for the process exception if any.
    */
   final int errorCode;
 }