Add support for starting a detached process

runtime/bin/process.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 BIN_PROCESS_H_
 #define BIN_PROCESS_H_
 
 #include "bin/builtin.h"
 #include "bin/io_buffer.h"
 #include "bin/lockers.h"
@@ skipping 69 matching lines @@
 class Process {
  public:
   // Start a new process providing access to stdin, stdout, stderr and
   // process exit streams.
   static int Start(const char* path,
                    char* arguments[],
                    intptr_t arguments_length,
                    const char* working_directory,
                    char* environment[],
                    intptr_t environment_length,
+                   bool detached,
                    intptr_t* in,
                    intptr_t* out,
                    intptr_t* err,
                    intptr_t* id,
                    intptr_t* exit_handler,
                    char** os_error_message);
 
   static bool Wait(intptr_t id,
                    intptr_t in,
                    intptr_t out,
@@ skipping 175 matching lines @@
   intptr_t data_size_;
 
   // Number of free bytes in the last node in the list.
   intptr_t free_size_;
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_PROCESS_H_