Dart: Avoid MojoResult and MojoHandleSignals constructors.

mojo/dart/packages/mojo/lib/src/fill_data.dart

Index: mojo/dart/packages/mojo/lib/src/fill_data.dart
diff --git a/mojo/dart/packages/mojo/lib/src/fill_data.dart b/mojo/dart/packages/mojo/lib/src/fill_data.dart
index c139a7c3c4c2182d70c4fcf6159c8108a7483f4e..0fa5ec6cf0a8d11f2acdec05be408a3aaf4062f6 100644
--- a/mojo/dart/packages/mojo/lib/src/fill_data.dart
+++ b/mojo/dart/packages/mojo/lib/src/fill_data.dart
@@ -15,12 +15,13 @@ class DataPipeFiller {
     _dataPosition = 0;
   }
 
-  MojoResult _doWrite() {
+  int _doWrite() {
     ByteData view = new ByteData.view(
         _data.buffer, _dataPosition, _data.lengthInBytes - _dataPosition);
     int written = _producer.write(view);
-    if (!_producer.status.isOk) {
-      throw 'Data pipe beginWrite failed: ${_producer.status}';
+    if (_producer.status != MojoResult.kOk) {
+      throw 'Data pipe beginWrite failed: '
+          '${MojoResult.string(_producer.status)}';
     }
     _dataPosition += written;
     return _producer.status;
@@ -29,18 +30,20 @@ class DataPipeFiller {
   void fill() {
     _eventSubscription.enableWriteEvents();
     _eventSubscription.subscribe((List<int> event) {
-      var mojoSignals = new MojoHandleSignals(event[1]);
-      if (mojoSignals.isWritable) {
-        MojoResult result = _doWrite();
-        if (_dataPosition >= _data.lengthInBytes || !result.isOk) {
+      int mojoSignals = event[1];
+      if (MojoHandleSignals.isWritable(mojoSignals)) {
+        int result = _doWrite();
+        if ((_dataPosition >= _data.lengthInBytes) ||
+            (result != MojoResult.kOk)) {
           _eventSubscription.close();
           _eventSubscription = null;
         }
-      } else if (mojoSignals.isPeerClosed) {
+      } else if (MojoHandleSignals.isPeerClosed(mojoSignals)) {
         _eventSubscription.close();
         _eventSubscription = null;
       } else {
-        throw 'Unexpected handle event: $mojoSignals';
+        String signals = MojoHandleSignals.string(mojoSignals);
+        throw 'Unexpected handle event: $signals';
       }
     });
   }