Issue 30238. Fix for subscribing for a notifications with already cached analysis result.

pkg/analyzer/lib/src/dart/analysis/driver.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:typed_data';
 
 import 'package:analyzer/context/context_root.dart';
 import 'package:analyzer/context/declared_variables.dart';
@@ skipping 651 matching lines @@
   /**
    * Return a [Future] that completes with a [AnalysisResult] for the Dart
    * file with the given [path]. If the file is not a Dart file or cannot
    * be analyzed, the [Future] completes with `null`.
    *
    * The [path] must be absolute and normalized.
    *
    * The [path] can be any file - explicitly or implicitly analyzed, or neither.
    *
    * If the driver has the cached analysis result for the file, it is returned.
+   * If [sendCachedToStream] is `true`, then the result is also reported into
+   * the [results] stream, just as if it were freshly computed.
    *
    * Otherwise causes the analysis state to transition to "analyzing" (if it is
    * not in that state already), the driver will produce the analysis result for
    * it, which is consistent with the current file state (including new states
    * of the files previously reported using [changeFile]), prior to the next
    * time the analysis state transitions to "idle".
    */
-  Future<AnalysisResult> getResult(String path) {
+  Future<AnalysisResult> getResult(String path,
+      {bool sendCachedToStream: false}) {
     if (!_fsState.hasUri(path)) {
       return new Future.value();
     }
 
     // Return the cached result.
     {
       AnalysisResult result = getCachedResult(path);
       if (result != null) {
+        if (sendCachedToStream) {
+          _resultController.add(result);
+        }
         return new Future.value(result);
       }
     }
 
     // Schedule analysis.
     var completer = new Completer<AnalysisResult>();
     _requestedFiles
         .putIfAbsent(path, () => <Completer<AnalysisResult>>[])
         .add(completer);
     _scheduler.notify(this);
@@ skipping 1365 matching lines @@
           libraryDeclarations.add(new TopLevelDeclarationInSource(
               file.source, declaration, isExported));
         }
       }
     }
 
     // We're not done yet.
     return false;
   }
 }