Revert "Change the way tasks are registered" (TBD)

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 fb0599db48ef6d65ff16b1bb4b61fda369765ec0..9a8f619a0c874ad0b074096c28554e9aa624d86c 100644
--- a/pkg/analyzer/lib/src/plugin/engine_plugin.dart
+++ b/pkg/analyzer/lib/src/plugin/engine_plugin.dart
@@ -10,9 +10,12 @@ import 'package:analyzer/src/generated/engine.dart'
     show InternalAnalysisContext;
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/src/task/dart_work_manager.dart';
+import 'package:analyzer/src/task/general.dart';
 import 'package:analyzer/src/task/html.dart';
 import 'package:analyzer/src/task/html_work_manager.dart';
+import 'package:analyzer/src/task/options.dart';
 import 'package:analyzer/src/task/options_work_manager.dart';
+import 'package:analyzer/src/task/yaml.dart';
 import 'package:analyzer/task/model.dart';
 import 'package:plugin/plugin.dart';
 
@@ -44,6 +47,12 @@ class EnginePlugin implements Plugin {
 
   /**
    * The simple identifier of the extension point that allows plugins to
+   * register new analysis tasks with the analysis engine.
+   */
+  static const String TASK_EXTENSION_POINT = 'task';
+
+  /**
+   * The simple identifier of the extension point that allows plugins to
    * register new work manager factories with the analysis engine.
    */
   static const String WORK_MANAGER_FACTORY_EXTENSION_POINT =
@@ -75,6 +84,12 @@ class EnginePlugin implements Plugin {
   ExtensionPoint<ListResultDescriptor<AnalysisError>> htmlErrorsExtensionPoint;
 
   /**
+   * The extension point that allows plugins to register new analysis tasks with
+   * the analysis engine.
+   */
+  ExtensionPoint<TaskDescriptor> taskExtensionPoint;
+
+  /**
    * The extension point that allows plugins to register new work manager
    * factories with the analysis engine.
    */
@@ -108,6 +123,11 @@ class EnginePlugin implements Plugin {
   @ExtensionPointId('HTML_ERRORS_EXTENSION_POINT_ID')
   List<ResultDescriptor> get htmlErrors => htmlErrorsExtensionPoint.extensions;
 
+  /**
+   * Return a list containing all of the task descriptors that were contributed.
+   */
+  List<TaskDescriptor> get taskDescriptors => taskExtensionPoint.extensions;
+
   @override
   String get uniqueIdentifier => UNIQUE_IDENTIFIER;
 
@@ -132,6 +152,9 @@ class EnginePlugin implements Plugin {
         new ExtensionPoint<ListResultDescriptor<AnalysisError>>(
             this, HTML_ERRORS_EXTENSION_POINT, null);
     registerExtensionPoint(htmlErrorsExtensionPoint);
+    taskExtensionPoint =
+        new ExtensionPoint<TaskDescriptor>(this, TASK_EXTENSION_POINT, null);
+    registerExtensionPoint(taskExtensionPoint);
     workManagerFactoryExtensionPoint = new ExtensionPoint<WorkManagerFactory>(
         this, WORK_MANAGER_FACTORY_EXTENSION_POINT, null);
     registerExtensionPoint(workManagerFactoryExtensionPoint);
@@ -139,6 +162,7 @@ class EnginePlugin implements Plugin {
 
   @override
   void registerExtensions(RegisterExtension registerExtension) {
+    _registerTaskExtensions(registerExtension);
     _registerWorkManagerFactoryExtensions(registerExtension);
     _registerDartErrorsForSource(registerExtension);
     _registerDartErrorsForUnit(registerExtension);
@@ -159,6 +183,80 @@ class EnginePlugin implements Plugin {
     registerExtension(HTML_ERRORS_EXTENSION_POINT_ID, HTML_DOCUMENT_ERRORS);
   }
 
+  void _registerTaskExtensions(RegisterExtension registerExtension) {
+    String taskId = TASK_EXTENSION_POINT_ID;
+    //
+    // Register general tasks.
+    //
+    registerExtension(taskId, GetContentTask.DESCRIPTOR);
+    //
+    // Register Dart tasks.
+    //
+    registerExtension(taskId, BuildCompilationUnitElementTask.DESCRIPTOR);
+    registerExtension(taskId, BuildDirectiveElementsTask.DESCRIPTOR);
+    registerExtension(taskId, BuildEnumMemberElementsTask.DESCRIPTOR);
+    registerExtension(taskId, BuildExportNamespaceTask.DESCRIPTOR);
+    registerExtension(taskId, BuildLibraryElementTask.DESCRIPTOR);
+    registerExtension(taskId, BuildPublicNamespaceTask.DESCRIPTOR);
+    registerExtension(taskId, BuildSourceExportClosureTask.DESCRIPTOR);
+    registerExtension(taskId, BuildTypeProviderTask.DESCRIPTOR);
+    registerExtension(taskId, ComputeConstantDependenciesTask.DESCRIPTOR);
+    registerExtension(taskId, ComputeConstantValueTask.DESCRIPTOR);
+    registerExtension(
+        taskId, ComputeInferableStaticVariableDependenciesTask.DESCRIPTOR);
+    registerExtension(taskId, ComputeLibraryCycleTask.DESCRIPTOR);
+    registerExtension(taskId, ComputeRequiredConstantsTask.DESCRIPTOR);
+    registerExtension(taskId, ContainingLibrariesTask.DESCRIPTOR);
+    registerExtension(taskId, DartErrorsTask.DESCRIPTOR);
+    registerExtension(taskId, EvaluateUnitConstantsTask.DESCRIPTOR);
+    registerExtension(taskId, GatherUsedImportedElementsTask.DESCRIPTOR);
+    registerExtension(taskId, GatherUsedLocalElementsTask.DESCRIPTOR);
+    registerExtension(taskId, GenerateHintsTask.DESCRIPTOR);
+    registerExtension(taskId, GenerateLintsTask.DESCRIPTOR);
+    registerExtension(taskId, InferInstanceMembersInUnitTask.DESCRIPTOR);
+    registerExtension(taskId, InferStaticVariableTypesInUnitTask.DESCRIPTOR);
+    registerExtension(taskId, InferStaticVariableTypeTask.DESCRIPTOR);
+    registerExtension(taskId, LibraryErrorsReadyTask.DESCRIPTOR);
+    registerExtension(taskId, LibraryUnitErrorsTask.DESCRIPTOR);
+    registerExtension(taskId, ParseDartTask.DESCRIPTOR);
+    registerExtension(taskId, PartiallyResolveUnitReferencesTask.DESCRIPTOR);
+    registerExtension(taskId, ReadyLibraryElement2Task.DESCRIPTOR);
+    registerExtension(taskId, ReadyLibraryElement5Task.DESCRIPTOR);
+    registerExtension(taskId, ReadyLibraryElement7Task.DESCRIPTOR);
+    registerExtension(taskId, ReadyResolvedUnitTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveConstantExpressionTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveDirectiveElementsTask.DESCRIPTOR);
+    registerExtension(taskId, ResolvedUnit7InLibraryClosureTask.DESCRIPTOR);
+    registerExtension(taskId, ResolvedUnit7InLibraryTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveInstanceFieldsInUnitTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveLibraryReferencesTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveLibraryTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveLibraryTypeNamesTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveTopLevelLibraryTypeBoundsTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveTopLevelUnitTypeBoundsTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveUnitTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveUnitTypeNamesTask.DESCRIPTOR);
+    registerExtension(taskId, ResolveVariableReferencesTask.DESCRIPTOR);
+    registerExtension(taskId, ScanDartTask.DESCRIPTOR);
+    registerExtension(taskId, StrongModeVerifyUnitTask.DESCRIPTOR);
+    registerExtension(taskId, VerifyUnitTask.DESCRIPTOR);
+    //
+    // Register HTML tasks.
+    //
+    registerExtension(taskId, DartScriptsTask.DESCRIPTOR);
+    registerExtension(taskId, HtmlErrorsTask.DESCRIPTOR);
+    registerExtension(taskId, ParseHtmlTask.DESCRIPTOR);
+    //
+    // Register YAML tasks.
+    //
+    registerExtension(taskId, ParseYamlTask.DESCRIPTOR);
+    //
+    // Register analysis option file tasks.
+    //
+    registerExtension(
+        TASK_EXTENSION_POINT_ID, GenerateOptionsErrorsTask.DESCRIPTOR);
+  }
+
   void _registerWorkManagerFactoryExtensions(
       RegisterExtension registerExtension) {
     String taskId = WORK_MANAGER_EXTENSION_POINT_ID;