Replace isAppropriateFor with suitabilityFor and start using it

pkg/analyzer/lib/src/task/model.dart

 // Copyright (c) 2015, 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 analyzer.src.task.model;
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/task/inputs.dart';
 import 'package:analyzer/task/model.dart';
 
@@ skipping 108 matching lines @@
   @override
   final CreateTaskInputs createTaskInputs;
 
   /**
    * A list of the analysis results that will be computed by the described task.
    */
   @override
   final List<ResultDescriptor> results;
 
   /**
-   * The function used to determine whether the described task is appropriate
-   * for a given target.
+   * The function used to determine whether the described task is suitable for
+   * a given target.
    */
-  final IsAppropriateFor _isAppropriateFor;
+  final SuitabilityFor _suitabilityFor;
 
   /**
    * Initialize a newly created task descriptor to have the given [name] and to
    * describe a task that takes the inputs built using the given [inputBuilder],
    * and produces the given [results]. The [buildTask] function will be used to
    * create the instance of [AnalysisTask] being described. If provided, the
    * [isAppropriateFor] function will be used to determine whether the task can
    * be used on a specific target.
    */
   TaskDescriptorImpl(
       this.name, this.buildTask, this.createTaskInputs, this.results,
-      {IsAppropriateFor isAppropriateFor})
-      : _isAppropriateFor = isAppropriateFor ?? _alwaysTrue;
+      {SuitabilityFor suitabilityFor})
+      : _suitabilityFor = suitabilityFor ?? _defaultSuitability;
 
   @override
   AnalysisTask createTask(AnalysisContext context, AnalysisTarget target,
       Map<String, dynamic> inputs) {
     AnalysisTask task = buildTask(context, target);
     task.inputs = inputs;
     return task;
   }
 
   @override
-  bool isAppropriateFor(AnalysisTarget target) => _isAppropriateFor(target);
+  TaskSuitability suitabilityFor(AnalysisTarget target) =>
+      _suitabilityFor(target);
 
   @override
   String toString() => name;
 
   /**
-   * The function that will be used to determine whether a task can be applied
-   * to a given target if no other function is provided.
+   * The function that will be used to determine the suitability of a task if no
+   * other function is provided.
    */
-  static bool _alwaysTrue(AnalysisTarget target) => true;
+  static TaskSuitability _defaultSuitability(AnalysisTarget target) =>
+      TaskSuitability.LOWEST;
 }