Always escape " in Process on Windows.

runtime/bin/process_patch.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.
 
 patch class _WindowsCodePageDecoder {
   /* patch */ static String _decodeBytes(List<int> bytes)
       native "SystemEncodingToString";
 }
 
 
@@ skipping 74 matching lines @@
     }
     int len = arguments.length;
     _arguments = new List<String>(len);
     for (int i = 0; i < len; i++) {
       var arg = arguments[i];
       if (arg is !String) {
         throw new ArgumentError("Non-string argument: $arg");
       }
       _arguments[i] = arguments[i];
       if (Platform.operatingSystem == 'windows') {
-        _arguments[i] = _windowsArgumentEscape(_arguments[i],
-                                               shellEscape: runInShell);
+        _arguments[i] = _windowsArgumentEscape(_arguments[i]);
       }
     }
 
     if (_workingDirectory != null && _workingDirectory is !String) {
       throw new ArgumentError(
           "WorkingDirectory is not a String: $_workingDirectory");
     }
 
     if (environment != null) {
       var env = environment;
@@ skipping 44 matching lines @@
       shellArguments.add("-c");
       for (var arg in arguments) {
         arg = arg.replaceAll("'", "'\"'\"'");
         commandLine.write(" '$arg'");
       }
       shellArguments.add(commandLine.toString());
     }
     return shellArguments;
   }
 
-  String _windowsArgumentEscape(String argument, { bool shellEscape: false }) {
+  String _windowsArgumentEscape(String argument) {
     var result = argument;
     if (argument.contains('\t') ||
         argument.contains(' ') ||
-        // TODO(ajohnsen): Remove shellEscape.
-        (shellEscape && argument.contains('"'))) {
+        argument.contains('"')) {
       // Produce something that the C runtime on Windows will parse
       // back as this string.
 
       // Replace any number of '\' followed by '"' with
       // twice as many '\' followed by '\"'.
       var backslash = '\\'.codeUnitAt(0);
       var sb = new StringBuffer();
       var nextPos = 0;
       var quotePos = argument.indexOf('"', nextPos);
       while (quotePos != -1) {
@@ skipping 208 matching lines @@
   const _ProcessResult(int this.pid,
                        int this.exitCode,
                        this.stdout,
                        this.stderr);
 
   final int pid;
   final int exitCode;
   final stdout;
   final stderr;
 }