merge to trunk all changes from 36817 until 37378 under the packages: polymer,

pkg/observe/lib/src/bindable.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.
 
 library observe.src.bindable;
 
 /// An object that can be data bound.
 // Normally this is used with 'package:template_binding'.
 // TODO(jmesserly): Node.bind polyfill calls this "observable"
 abstract class Bindable {
   // TODO(jmesserly): since we have "value", should open be a void method?
-  // TODO(jmesserly): not sure how I feel about open taking a variable number
-  // of arguments, but it's the easiest way to make CompoundObserver work.
+  // Dart note: changed setValue to be "set value" and discardChanges() to
+  // be "get value". Also "set value" implies discard changes.
+  // TOOD(jmesserly): is this change too subtle? Is there any other way to
+  // make Bindable friendly in a world with getters/setters?
 
   /// Initiates observation and returns the initial value.
   /// The callback will be called with the updated [value].
   ///
   /// Some subtypes may chose to provide additional arguments, such as
   /// [PathObserver] providing the old value as the second argument.
   /// However, they must support callbacks with as few as 0 or 1 argument.
   /// This can be implemented by performing an "is" type test on the callback.
   open(callback);
 
   /// Stops future notifications and frees the reference to the callback passed
   /// to [open], so its memory can be collected even if this Bindable is alive.
   void close();
 
   /// Gets the current value of the bindings.
   get value;
 
   /// This can be implemented for two-way bindings. By default does nothing.
   /// Note: setting the value of a [Bindable] must not call the [callback] with
   /// the new value. Any pending change notifications must be discarded.
   set value(newValue) {}
 }