Add Process.shell and Process.runShell.

tests/standalone/io/process_shell_test.dart

+// Copyright (c) 2013, 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.
+
+import "dart:io";
+
+void testRunShell() {
+  test(args) {
+    var options = new Options();
+    var path = new Path(options.script);
+    path = path.directoryPath.join(new Path("process_echo_util.dart"));
+    Process.runShell(options.executable, [path.toString()]..addAll(args))
+        .then((result) {
+          result = result.stdout.split("\n");
+          print(result);
+          if (result.length - 1 != args.length) {
+            throw "wrong number of args: $args vs $result";
+          }
+          for (int i = 0; i < args.length; i++) {
+            if (args[i] != result[i]) {
+              throw "bad result at $i: ${args[i]} vs ${result[i]}";
+            }
+          }
+        });
+  }
+  test(["\""]);
+  test(["'"]);
+  test(["'\"\"'\"'\"'"]);
+  test(["'\"\"'", "\"'\"'"]);
+  test(["'\$HOME'"]);
+  test(["'\$tmp'"]);
+}
+
+void testShell() {
+  test(args, expected) {
+    var options = new Options();
+    var path = new Path(options.script);
+    path = path.directoryPath.join(new Path("process_echo_util.dart"));
+    var command = "${options.executable} $path $args";
+    Process.runShell(command, [])
+        .then((result) {
+          result = result.stdout.split("\n");
+          if (result.length - 1 != expected.length) {
+            throw "wrong number of args: $expected vs $result";
+          }
+          for (int i = 0; i < expected.length; i++) {
+            if (expected[i] != result[i]) {
+              throw "bad result at $i: ${expected[i]} vs ${result[i]}";
+            }
+          }
+        });
+  }
+  test("arg", ["arg"]);
+  test("arg1 arg2", ["arg1", "arg2"]);
+  if (Platform.operatingSystem != 'windows') {
+    test("arg1 arg2 > /dev/null", []);
+  }
+}
+
+void main() {
+  testRunShell();
+  testShell();
+}
+