Support abstract getters without parameters.

dart/lib/compiler/implementation/elements/elements.dart

Index: dart/lib/compiler/implementation/elements/elements.dart
diff --git a/dart/lib/compiler/implementation/elements/elements.dart b/dart/lib/compiler/implementation/elements/elements.dart
index dd10c069167c01e1b8c95bf0553d1fcb72329dff..49ac60741b5489b744782906127f984a0dcf36dc 100644
--- a/dart/lib/compiler/implementation/elements/elements.dart
+++ b/dart/lib/compiler/implementation/elements/elements.dart
@@ -1059,7 +1059,7 @@ abstract class TypeDeclarationElement implements Element {
    */
   // TODO(johnniwinther): Find a (better) way to decouple [typeVariables] from
   // [Compiler].
-  abstract Link<Type> get typeVariables();
+  abstract Link<Type> get typeVariables;
 
   /**
    * Creates the type variables, their type and corresponding element, for the
@@ -1614,7 +1614,7 @@ class MetadataAnnotation {
    * The compile-time constant which this annotation resolves to.
    * In the mirror system, this would be an object mirror.
    */
-  abstract Constant get value();
+  abstract Constant get value;
   Element annotatedElement;
   int resolutionState;