Adding MOJO_HANDLE_SIGNAL_PEER_CLOSED to be notified when a peer is closed.

mojo/public/dart/src/types.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 core;
 
 
 class MojoResult {
   static const int kOk = 0;
@@ skipping 104 matching lines @@
       default: return "<invalid result>";
     }
   }
 }
 
 
 class MojoHandleSignals {
   static const int NONE = 0;
   static const int READABLE = 1 << 0;
   static const int WRITABLE = 1 << 1;
+  static const int PEER_CLOSED = 1 << 2;
   static const int READWRITE = READABLE | WRITABLE;
 
   static bool isNone(int mask) => mask == NONE;
   static bool isReadable(int mask) => (mask & READABLE) == READABLE;
   static bool isWritable(int mask) => (mask & WRITABLE) == WRITABLE;
   static bool isReadWrite(int mask) => (mask & READWRITE) == READWRITE;
   static int toggleWrite(int mask) =>
     isWritable(mask) ? (mask & ~WRITABLE) : (mask | WRITABLE);
 }
 
 
 class MojoHandleSignalsState {
   const MojoHandleSignalsState(this.satisfied_signals,
                                this.satisfiable_signals);
   final int satisfied_signals;
   final int satisfiable_signals;
 }