Last performed task diagnostics.

pkg/analyzer/lib/task/model.dart

Index: pkg/analyzer/lib/task/model.dart
diff --git a/pkg/analyzer/lib/task/model.dart b/pkg/analyzer/lib/task/model.dart
index 791f8327fba27085fc85918b229dfc5a7da0a596..f550495d0f0363784de865add49487a48d36e9da 100644
--- a/pkg/analyzer/lib/task/model.dart
+++ b/pkg/analyzer/lib/task/model.dart
@@ -79,6 +79,11 @@ abstract class AnalysisTarget {
  */
 abstract class AnalysisTask {
   /**
+   * A queue storing the last 10 task descriptions for diagnostic purposes.
+   */
+  static final LimitedQueue<String> LAST_TASKS = new LimitedQueue<String>(10);
+
+  /**
    * A table mapping the types of analysis tasks to the number of times each
    * kind of task has been performed.
    */
@@ -266,6 +271,11 @@ abstract class AnalysisTask {
   void _safelyPerform() {
     try {
       //
+      // Store task description for diagnostics.
+      //
+      LAST_TASKS.add(description);
+
+      //
       // Report that this task is being performed.
       //
       String contextName = context.name;