Use IndexContributor(s) in LocalIndex.

pkg/analysis_server/test/services/search/search_engine_test.dart

Index: pkg/analysis_server/test/services/search/search_engine_test.dart
diff --git a/pkg/analysis_server/test/services/search/search_engine_test.dart b/pkg/analysis_server/test/services/search/search_engine_test.dart
index 5e1c0e6dd48786c428f219aef35ddedefb1d065a..3e411d22e0aa81d88a9ae2cc588c3c1ac4915870 100644
--- a/pkg/analysis_server/test/services/search/search_engine_test.dart
+++ b/pkg/analysis_server/test/services/search/search_engine_test.dart
@@ -357,8 +357,8 @@ part 'unitB.dart';
     LibraryElement element = testLibraryElement;
     CompilationUnitElement elementA = element.parts[0];
     CompilationUnitElement elementB = element.parts[1];
-    index.indexUnit(context, elementA.computeNode());
-    index.indexUnit(context, elementB.computeNode());
+    index.index(context, elementA.computeNode());
+    index.index(context, elementB.computeNode());
     var expected = [
       new ExpectedMatch(elementA, MatchKind.REFERENCE,
           codeA.indexOf('lib; // A'), 'lib'.length),
@@ -628,7 +628,7 @@ class NoMatchABCDE {}
 
   void _indexTestUnit(String code) {
     resolveTestUnit(code);
-    index.indexUnit(context, testUnit);
+    index.index(context, testUnit);
   }
 
   Future _verifyReferences(