feat(dart/transform): Fix handling of Dart keywords

Use `package:analyzer`'s list of Dart keywords to ensure we are properly
reporting usages of Dart keywords as runtime errors.

modules/angular2/src/transform/common/property_utils.dart

@@ -0,0 +1,33 @@
+library angular2.transform.common.property_utils;
+
+import 'package:analyzer/src/generated/scanner.dart' show Keyword;
+
+/// Whether `name` is a valid property name.
+bool isValid(String name) => !Keyword.keywords.containsKey(name);
+
+/// Prepares [name] to be emitted inside a string.
+String sanitize(String name) => name.replaceAll('\$', '\\\$');
+
+/// Get a string usable as a lazy invalid setter, that is, one which will
+/// `throw` immediately upon use.
+String lazyInvalidSetter(String setterName) {
+  var sName = sanitize(setterName);
+  return ''' '$sName': (o, v) => '''
+      ''' throw 'Invalid setter name "$sName" is a Dart keyword.' ''';
+}
+
+/// Get a string usable as a lazy invalid getter, that is, one which will
+/// `throw` immediately upon use.
+String lazyInvalidGetter(String getterName) {
+  var sName = sanitize(getterName);
+  return ''' '$sName': (o) => '''
+      ''' throw 'Invalid getter name "$sName" is a Dart keyword.' ''';
+}
+
+/// Get a string usable as a lazy invalid method, that is, one which will
+/// `throw` immediately upon use.
+String lazyInvalidMethod(String methodName) {
+  var sName = sanitize(methodName);
+  return ''' '$sName': (o, args) => '''
+      ''' throw 'Invalid method name "$sName" is a Dart keyword.' ''';
+}