Fix for subscribing for notifications for files in packages.

pkg/analysis_server/test/domain_completion_test.dart

Index: pkg/analysis_server/test/domain_completion_test.dart
diff --git a/pkg/analysis_server/test/domain_completion_test.dart b/pkg/analysis_server/test/domain_completion_test.dart
index 83dd415b308b4a4d862c681f8f0e52ba2bf2ac11..20f6a4197accdafce3c7c71f5cb0278c27b99b5b 100644
--- a/pkg/analysis_server/test/domain_completion_test.dart
+++ b/pkg/analysis_server/test/domain_completion_test.dart
@@ -192,8 +192,9 @@ class CompletionManagerTest extends AbstractAnalysisTest {
     sendRequest(testFile);
     return pumpEventQueue().then((_) {
       expect(completionDomain.manager, isNotNull);
+      ContextSourcePair contextSource = server.getContextSourcePair(testFile2);
       ChangeSet changeSet = new ChangeSet();
-      changeSet.changedSource(server.getSource(testFile2));
+      changeSet.changedSource(contextSource.source);
       completionDomain.sourcesChanged(new SourcesChangedEvent(changeSet));
       expect(completionDomain.manager, isNull);
     });
@@ -617,9 +618,16 @@ class Test_AnalysisServer extends AnalysisServer {
       : super(channel, resourceProvider, packageMapProvider, index,
           analysisServerOptions, defaultSdk, instrumentationService);
 
+  @override
   AnalysisContext getAnalysisContext(String path) {
     return mockContext;
   }
+
+  @override
+  ContextSourcePair getContextSourcePair(String path) {
+    ContextSourcePair pair = super.getContextSourcePair(path);
+    return new ContextSourcePair(mockContext, pair.source);
+  }
 }
 
 /**