Associate excludes with context data.

pkg/analysis_server/lib/src/context_manager.dart

Index: pkg/analysis_server/lib/src/context_manager.dart
diff --git a/pkg/analysis_server/lib/src/context_manager.dart b/pkg/analysis_server/lib/src/context_manager.dart
index 585da4628b77350130670db2dd01b158c96cf6a5..e77ae2261d71a7eda0720fd3c6c3cf49cfbd9d61 100644
--- a/pkg/analysis_server/lib/src/context_manager.dart
+++ b/pkg/analysis_server/lib/src/context_manager.dart
@@ -23,6 +23,7 @@ import 'package:analyzer/source/path_filter.dart';
 import 'package:analyzer/source/pub_package_map_provider.dart';
 import 'package:analyzer/source/sdk_ext.dart';
 import 'package:analyzer/src/context/context.dart' as context;
+import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/context/source.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
@@ -625,7 +626,7 @@ class ContextManagerImpl implements ContextManager {
     if (analyzer is Map) {
       // Set ignore patterns.
       YamlList exclude = analyzer[AnalyzerOptions.exclude];
-      List<String> excludeList = _toStringList(exclude);
+      List<String> excludeList = toStringList(exclude);
       if (excludeList != null) {
         setIgnorePatternsForContext(info, excludeList);
       }
@@ -1594,25 +1595,6 @@ class ContextManagerImpl implements ContextManager {
   }
 
   /**
-   * If all of the elements of [list] are strings, return a list of strings
-   * containing the same elements. Otherwise, return `null`.
-   */
-  List<String> _toStringList(YamlList list) {
-    if (list == null) {
-      return null;
-    }
-    List<String> stringList = <String>[];
-    for (var element in list) {
-      if (element is String) {
-        stringList.add(element);
-      } else {
-        return null;
-      }
-    }
-    return stringList;
-  }
-
-  /**
    * If the given [object] is a map, and all of the keys in the map are strings,
    * return a map containing the same mappings. Otherwise, return `null`.
    */