Flush results when contexts are made idle.

pkg/analyzer/lib/src/generated/engine.dart

Index: pkg/analyzer/lib/src/generated/engine.dart
diff --git a/pkg/analyzer/lib/src/generated/engine.dart b/pkg/analyzer/lib/src/generated/engine.dart
index aa9a74b2b384675b65a6385dbb8c23366ac4eecf..7e0f08a4c12ae571d55c9efc39227cfa49b4b843 100644
--- a/pkg/analyzer/lib/src/generated/engine.dart
+++ b/pkg/analyzer/lib/src/generated/engine.dart
@@ -2084,6 +2084,16 @@ abstract class InternalAnalysisContext implements AnalysisContext {
   List<AnalysisTarget> get explicitTargets;
 
   /**
+   * Return `true` if the context is active, i.e. is being analyzed now.
+   */
+  bool get isActive;
+
+  /**
+   * Specify whether the context is active, i.e. is being analyzed now.
+   */
+  set isActive(bool value);
+
+  /**
    * Return the [StreamController] reporting [InvalidatedResult]s for everything
    * in this context's cache.
    */