Cleanup method signatures.

BUG=
R=jmesserly@google.com

Review URL: https://codereview.appspot.com/198060043
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 79efbe7..b6786e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+#### 0.12.2+1
+  * Cleanup some method signatures.
+
 #### 0.12.2
   * Updated to match release 0.5.1
     [observe-js#d530515](https://github.com/Polymer/observe-js/commit/d530515).
diff --git a/lib/src/observer_transform.dart b/lib/src/observer_transform.dart
index 2ca9fda..7fab555 100644
--- a/lib/src/observer_transform.dart
+++ b/lib/src/observer_transform.dart
@@ -50,7 +50,7 @@
         _getTransformer = computeValue,
         _setTransformer = setValue;
 
-  open(callback(value)) {
+  open(callback) {
     _notifyCallback = callback;
     _value = _getTransformer(_bindable.open(_observedCallback));
     return _value;
diff --git a/lib/src/path_observer.dart b/lib/src/path_observer.dart
index 297bd1d..d0eb85d 100644
--- a/lib/src/path_observer.dart
+++ b/lib/src/path_observer.dart
@@ -41,7 +41,7 @@
   PropertyPath get path => _path;
 
   /// Sets the value at this path.
-  void set value(Object newValue) {
+  void set value(newValue) {
     if (_path != null) _path.setValueFrom(_object, newValue);
   }
 
@@ -289,8 +289,7 @@
     // TODO(sigmund): should we also support using checking dynamically for
     // whether the type practically implements the indexer API
     // (smoke.hasInstanceMethod(type, const Symbol('[]')))?
-    if (object is Indexable<String, dynamic> ||
-        object is Map<String, dynamic> && !_MAP_PROPERTIES.contains(property)) {
+    if (object is Indexable || object is Map && !_MAP_PROPERTIES.contains(property)) {
       return object[smoke.symbolToName(property)];
     }
     try {
@@ -320,8 +319,7 @@
     }
   } else if (property is Symbol) {
     // Support indexer if available, e.g. Maps or polymer_expressions Scope.
-    if (object is Indexable<String, dynamic> ||
-        object is Map<String, dynamic> && !_MAP_PROPERTIES.contains(property)) {
+    if (object is Indexable || object is Map && !_MAP_PROPERTIES.contains(property)) {
       object[smoke.symbolToName(property)] = value;
       return true;
     }
diff --git a/pubspec.yaml b/pubspec.yaml
index 8798512..7dd146a 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: observe
-version: 0.12.2
+version: 0.12.2+1
 author: Polymer.dart Authors <web-ui-dev@dartlang.org>
 description: >
   Observable properties and objects for use in template_binding.
@@ -13,7 +13,7 @@
   barback: '>=0.14.2 <0.16.0'
   logging: '>=0.9.0 <0.10.0'
   path: '>=0.9.0 <2.0.0'
-  smoke: '>=0.1.0 <0.3.0'
+  smoke: '>=0.1.0 <0.4.0'
   source_maps: '>=0.9.4 <0.11.0'
   source_span: '>=1.0.0 <2.0.0'
   utf: '>=0.9.0 <0.10.0'