Add AnalysisContext.onResultComputed().

pkg/analyzer/lib/src/context/context.dart

Index: pkg/analyzer/lib/src/context/context.dart
diff --git a/pkg/analyzer/lib/src/context/context.dart b/pkg/analyzer/lib/src/context/context.dart
index 303101b8edf861b3ab38d86f8db829e137a35a32..6467bfb18ca417f466b3810c7312d13eb803464d 100644
--- a/pkg/analyzer/lib/src/context/context.dart
+++ b/pkg/analyzer/lib/src/context/context.dart
@@ -1015,6 +1015,11 @@ class AnalysisContextImpl implements InternalAnalysisContext {
   }
 
   @override
+  Stream<ComputedResult> onResultComputed(ResultDescriptor descriptor) {
+    return driver.onResultComputed(descriptor);
+  }
+
+  @override
   CompilationUnit parseCompilationUnit(Source source) {
     if (!AnalysisEngine.isDartFileName(source.shortName)) {
       return null;
@@ -1901,36 +1906,6 @@ class PendingFuture<T> {
 }
 
 /**
- * [ResultComputedEvent] describes a value computed for a [ResultDescriptor].
- */
-class ResultComputedEvent<V> {
-  /**
-   * The context in which the value was computed.
-   */
-  final AnalysisContext context;
-
-  /**
-   * The descriptor of the result which was computed.
-   */
-  final ResultDescriptor<V> descriptor;
-
-  /**
-   * The target for which the result was computed.
-   */
-  final AnalysisTarget target;
-
-  /**
-   * The computed value.
-   */
-  final V value;
-
-  ResultComputedEvent(this.context, this.descriptor, this.target, this.value);
-
-  @override
-  String toString() => '$value for $descriptor of $target in $context';
-}
-
-/**
  * An [AnalysisContext] that only contains sources for a Dart SDK.
  */
 class SdkAnalysisContext extends AnalysisContextImpl {