Add optional workingDirectory argument to Process.start.

runtime/bin/process_linux.cc

 // 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.
 
 #include "bin/process.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
@@ skipping 115 matching lines @@
         exec_control_fd, os_error_message, strlen(os_error_message) + 1);
   }
   close(exec_control_fd);
   exit(1);
 }
 
 
 int Process::Start(const char* path,
                    char* arguments[],
                    intptr_t arguments_length,
+                   const char* working_directory,
                    intptr_t* in,
                    intptr_t* out,
                    intptr_t* err,
                    intptr_t* id,
                    intptr_t* exit_event,
                    char* os_error_message,
                    int os_error_message_len) {
   pid_t pid;
   int read_in[2];  // Pipe for stdout to child process.
   int read_err[2];  // Pipe for stderr to child process.
@@ skipping 107 matching lines @@
     if (dup2(read_in[1], STDOUT_FILENO) == -1) {
       ReportChildError(exec_control[1]);
     }
     close(read_in[1]);
 
     if (dup2(read_err[1], STDERR_FILENO) == -1) {
       ReportChildError(exec_control[1]);
     }
     close(read_err[1]);
 
+    if (working_directory != NULL && chdir(working_directory) == -1) {
+      ReportChildError(exec_control[1]);
+    }
+
     execvp(path, const_cast<char* const*>(program_arguments));
     ReportChildError(exec_control[1]);
   }
 
   // The arguments for the spawned process are not needed any longer.
   delete[] program_arguments;
 
   int event_fds[2];
   result = pipe(event_fds);
   if (result < 0) {
@@ skipping 73 matching lines @@
   if (result == -1) {
     return false;
   }
   return true;
 }
 
 
 void Process::Exit(intptr_t id) {
   RemoveProcess(id);
 }