Use native fields for process pid and fix bug that allowed killing

runtime/bin/process.cc

 // 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.
 
 #include "bin/dartutils.h"
 #include "bin/process.h"
 #include "bin/socket.h"
 
 #include "include/dart_api.h"
 
 
+static const int kProcessIdNativeField = 0;
+
+
 // Extract an array of C strings from a list of Dart strings.
 static char** ExtractCStringList(Dart_Handle strings,
                                  Dart_Handle status_handle,
                                  const char* error_msg,
                                  intptr_t* length) {
   static const intptr_t kMaxArgumentListLength = 1024 * 1024;
   ASSERT(Dart_IsList(strings));
   intptr_t len = 0;
   Dart_Handle result = Dart_ListLength(strings, &len);
   if (Dart_IsError(result)) {
@@ skipping 109 matching lines @@
                                   &out,
                                   &err,
                                   &pid,
                                   &exit_event,
       os_error_message, kMaxChildOsErrorMessageLength);
   if (error_code == 0) {
     Socket::SetSocketIdNativeField(in_handle, in);
     Socket::SetSocketIdNativeField(out_handle, out);
     Socket::SetSocketIdNativeField(err_handle, err);
     Socket::SetSocketIdNativeField(exit_handle, exit_event);
-    DartUtils::SetIntegerField(process, "_pid", pid);
+    Process::SetProcessIdNativeField(process, pid);
   } else {
     DartUtils::SetIntegerField(
         status_handle, "_errorCode", error_code);
     DartUtils::SetStringField(
         status_handle, "_errorMessage", os_error_message);
   }
   delete[] string_args;
   delete[] string_environment;
   Dart_SetReturnValue(args, Dart_NewBoolean(error_code == 0));
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(Process_Kill)(Dart_NativeArguments args) {
   Dart_EnterScope();
-  intptr_t pid = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 1));
+  Dart_Handle process = Dart_GetNativeArgument(args, 1);
+  intptr_t pid = -1;
+  Process::GetProcessIdNativeField(process, &pid);
   int signal = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
   bool success = Process::Kill(pid, signal);
   Dart_SetReturnValue(args, Dart_NewBoolean(success));
   Dart_ExitScope();
 }
+
+
+Dart_Handle Process::GetProcessIdNativeField(Dart_Handle process,
+                                             intptr_t* pid) {
+  return Dart_GetNativeInstanceField(process, kProcessIdNativeField, pid);
+}
+
+
+Dart_Handle Process::SetProcessIdNativeField(Dart_Handle process,
+                                             intptr_t pid) {
+  return Dart_SetNativeInstanceField(process, kProcessIdNativeField, pid);
+}