Add hook for listening to implicitly analyzed files

pkg/analyzer/test/src/context/context_test.dart

Index: pkg/analyzer/test/src/context/context_test.dart
diff --git a/pkg/analyzer/test/src/context/context_test.dart b/pkg/analyzer/test/src/context/context_test.dart
index 7bc47ba7aebdac6ce85f8d12e3dd62d69f9f4cfe..8f960348427ad4e451274a5a426c00c22bd5bec5 100644
--- a/pkg/analyzer/test/src/context/context_test.dart
+++ b/pkg/analyzer/test/src/context/context_test.dart
@@ -55,6 +55,32 @@ main() {
 
 @reflectiveTest
 class AnalysisContextImplTest extends AbstractContextTest {
+  Future fail_analyzedSources_removed() async {
+    AnalyzedSourcesListener listener = new AnalyzedSourcesListener();
+    context.implicitAnalysisEvents.listen(listener.onData);
+    //
+    // Create a file that references an file that is not explicitly being
+    // analyzed and fully analyze it. Ensure that the listener is told about
+    // the implicitly analyzed file.
+    //
+    Source sourceA = newSource('/a.dart', "library a; import 'b.dart';");
+    Source sourceB = newSource('/b.dart', "library b;");
+    ChangeSet changeSet = new ChangeSet();
+    changeSet.addedSource(sourceA);
+    context.applyChanges(changeSet);
+    context.computeErrors(sourceA);
+    await pumpEventQueue();
+    listener.expectAnalyzed(sourceB);
+    //
+    // Remove the reference and ensure that the listener is told that we're no
+    // longer implicitly analyzing the file.
+    //
+    context.setContents(sourceA, "library a;");
+    context.computeErrors(sourceA);
+    await pumpEventQueue();
+    listener.expectNotAnalyzed(sourceB);
+  }
+
   void fail_performAnalysisTask_importedLibraryDelete_html() {
     // NOTE: This was failing before converting to the new task model.
     Source htmlSource = addSource("/page.html", r'''
@@ -90,6 +116,24 @@ class AnalysisContextImplTest extends AbstractContextTest {
     super.tearDown();
   }
 
+  Future test_analyzedSources_added() async {
+    AnalyzedSourcesListener listener = new AnalyzedSourcesListener();
+    context.implicitAnalysisEvents.listen(listener.onData);
+    //
+    // Create a file that references an file that is not explicitly being
+    // analyzed and fully analyze it. Ensure that the listener is told about
+    // the implicitly analyzed file.
+    //
+    Source sourceA = newSource('/a.dart', "library a; import 'b.dart';");
+    Source sourceB = newSource('/b.dart', "library b;");
+    ChangeSet changeSet = new ChangeSet();
+    changeSet.addedSource(sourceA);
+    context.applyChanges(changeSet);
+    context.computeErrors(sourceA);
+    await pumpEventQueue();
+    listener.expectAnalyzed(sourceB);
+  }
+
   Future test_applyChanges_add() {
     SourcesChangedListener listener = new SourcesChangedListener();
     context.onSourcesChanged.listen(listener.onData);