Convert EnginePlugin.taskDescriptors into a getter.

pkg/analyzer/lib/src/plugin/engine_plugin.dart

Index: pkg/analyzer/lib/src/plugin/engine_plugin.dart
diff --git a/pkg/analyzer/lib/src/plugin/engine_plugin.dart b/pkg/analyzer/lib/src/plugin/engine_plugin.dart
index 3b1090f6d798d62d106a46dfe8cfb32ed7f4b13b..acd631855ede944932767af1e3bf0322ca6cda0d 100644
--- a/pkg/analyzer/lib/src/plugin/engine_plugin.dart
+++ b/pkg/analyzer/lib/src/plugin/engine_plugin.dart
@@ -37,6 +37,11 @@ class EnginePlugin implements Plugin {
    */
   EnginePlugin();
 
+  /**
+   * Return a list containing all of the task descriptors that were contributed.
+   */
+  List<TaskDescriptor> get taskDescriptors => taskExtensionPoint.extensions;
+
   @override
   String get uniqueIdentifier => UNIQUE_IDENTIFIER;
 
@@ -83,13 +88,6 @@ class EnginePlugin implements Plugin {
   }
 
   /**
-   * Return a list containing all of the task descriptors that were contributed.
-   */
-  List<TaskDescriptor> taskDescriptors() {
-    return taskExtensionPoint.extensions;
-  }
-
-  /**
    * Validate the given extension by throwing an [ExtensionError] if it is not a
    * valid domain.
    */