Initial re-write of analysis context for the new task model

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

Index: pkg/analyzer/lib/src/task/manager.dart
diff --git a/pkg/analyzer/lib/src/task/manager.dart b/pkg/analyzer/lib/src/task/manager.dart
index 71986abb7c9fe07ea93207b5a3a9add5f01be74b..eebc08491fdea0fa1ef13f0b43babc5de5cf7d7a 100644
--- a/pkg/analyzer/lib/src/task/manager.dart
+++ b/pkg/analyzer/lib/src/task/manager.dart
@@ -67,6 +67,14 @@ class TaskManager {
   }
 
   /**
+   * Add the task descriptors in the given list of [descriptors] to the list of
+   * analysis task descriptors that can be used to compute analysis results.
+   */
+  void addTaskDescriptors(List<TaskDescriptor> descriptors) {
+    descriptors.forEach(addTaskDescriptor);
+  }
+
+  /**
    * Find a task that will compute the given [result] for the given [target].
    */
   TaskDescriptor findTask(AnalysisTarget target, ResultDescriptor result) {