rename completion computer to contributor

pkg/analysis_server/test/services/completion/arglist_computer_test.dart

 // Copyright (c) 2014, 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.
 
 library test.services.completion.dart.arglist;
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/arglist_computer.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../reflective_tests.dart';
 import 'completion_test_util.dart';
 
 main() {
   groupSep = ' | ';
-  runReflectiveTests(ArgListComputerTest);
+  runReflectiveTests(ArgListContributorTest);
 }
 
 @reflectiveTest
-class ArgListComputerTest extends AbstractCompletionTest {
+class ArgListContributorTest extends AbstractCompletionTest {
   @override
-  void setUpComputer() {
-    computer = new ArgListComputer();
+  void setUpContributor() {
+    contributor = new ArgListContributor();
   }
 
   test_ArgumentList_imported_function_0() {
     // ArgumentList  MethodInvocation  ExpressionStatement  Block
     addSource('/libA.dart', '''
       library A;
       bool hasLength(int expected) { }
       expect() { }
       void baz() { }''');
     addTestSource('''
@@ skipping 72 matching lines @@
       class B {
         expect(arg, int blat) { }
         void foo() {expect(^)}}
       String bar() => true;''');
     computeFast();
     return computeFull((bool result) {
       assertSuggestArgumentList(['arg', 'blat'], ['dynamic', 'int']);
     });
   }
 }