Make MojoResults positive.

mojo/public/dart/src/handle_watcher.dart

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 part of internal;
 
 // The MojoHandleWatcher sends a stream of events to application isolates that
 // register Mojo handles with it. Application isolates make the following calls:
 //
 // add(handle, port, signals) - Instructs the MojoHandleWatcher isolate to add
@@ skipping 12 matching lines @@
   static const int ADD = 0;
   static const int REMOVE = 1;
   static const int CLOSE = 2;
   static const int TIMER = 3;
   static const int SHUTDOWN = 4;
 
   static const int kMojoHandleInvalid = 0;
   static const int kDeadlineIndefinite = -1;
 
   static const int kMojoResultOk = 0;
-  static const int kMojoResultDeadlineExceeded = -4;
-  static const int kMojoResultFailedPrecondition = -9;
+  static const int kMojoResultDeadlineExceeded = 4;
+  static const int kMojoResultFailedPrecondition = 9;
 
   static const int kMojoSignalsReadable = (1 << 0);
   static const int kMojoSignalsWritable = (1 << 1);
   static const int kMojoSignalsPeerClosed = (1 << 2);
   static const int kMojoSignalsAll =
       kMojoSignalsReadable | kMojoSignalsWritable | kMojoSignalsPeerClosed;
 
   static int _encodeCommand(int cmd, [int signals = 0]) =>
       (cmd << 3) | (signals & kMojoSignalsAll);
   static int _decodeCommand(int cmd) {
@@ skipping 299 matching lines @@
 
   static int remove(int mojoHandle) {
     return _sendControlData(mojoHandle, null, _encodeCommand(REMOVE));
   }
 
   static int timer(Object ignored, SendPort port, int deadline) {
     // The deadline will be unwrapped before sending to the handle watcher.
     return _sendControlData(deadline, port, _encodeCommand(TIMER));
   }
 }