Remove unused import in polymer, fix comment.

pkg/polymer/lib/src/instance.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.
 
 part of polymer;
 
 /// Use this annotation to publish a field as an attribute. For example:
 ///
 ///     class MyPlaybackElement extends PolymerElement {
 ///       // This will be available as an HTML attribute, for example:
@@ skipping 608 matching lines @@
     return true;
   }
 
   void unregisterObservers() {
     if (_observers == null) return;
     for (var sub in _observers.values) sub.cancel();
     _observers.clear();
     _observers = null;
   }
 
-  /// Bind a [property] in this object to a [path] in model. *Note* in Dart it

[Siggi Cherem (dart-lang), 2014/05/07 17:24:39]

this [path] was marking the import as 'used', so the analyzer didn't report the
warning.

-  /// is necessary to also define the field:
-  ///
-  ///     var myProperty;
-  ///
-  ///     ready() {
-  ///       super.ready();
-  ///       bindProperty(#myProperty, this, 'myModel.path.to.otherProp');

[Jennifer Messerly, 2014/05/07 19:28:53]

I fixed this code snippet in my port without removing it.

All it needs is:

bindProperty(#myProperty,
    new PathObserver(this, 'myModel.path.to.otherProp'));

[Siggi Cherem (dart-lang), 2014/05/07 19:34:48]

Done

-  ///     }
+  /// Bind the [name] property in this element to [bindable].
   Bindable bindProperty(Symbol name, Bindable bindable) {
     // Dart note: normally we only reach this code when we know it's a
     // property, but if someone uses bindProperty directly they might get a
     // NoSuchMethodError either from the getField below, or from the setField
     // inside PolymerBinding. That doesn't seem unreasonable, but it's a slight
     // difference from Polymer.js behavior.
 
     if (_bindLog.isLoggable(Level.FINE)) {
       _bindLog.fine('bindProperty: [$bindable] to [${localName}].[name]');
     }
@@ skipping 372 matching lines @@
     if (_sub != null) {
       if (_eventsLog.isLoggable(Level.FINE)) {
         _eventsLog.fine(
             'event.remove: [$_node].$_eventName => [$_model].$_path())');
       }
      _sub.cancel();
       _sub = null;
     }
   }
 }