Add colon to switch cases and default

pkg/analysis_server/test/services/completion/statement/statement_completion_test.dart

 // Copyright (c) 2017, 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.statement;
 
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/statement/statement_completion.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:test/test.dart';
@@ skipping 747 matching lines @@
   int v = 1;
   ////
 }
 ''',
         (s) => _afterLast(s, '  '));
   }
 }
 
 @reflectiveTest
 class _SwitchCompletionTest extends StatementCompletionTest {
+  test_caseNoColon() async {
+    await _prepareCompletion(
+        'label',
+        '''
+main(x) {
+  switch (x) {
+    case label
+  }
+}
+''',
+        atEnd: true);
+    _assertHasChange(
+        'Complete switch-statement',
+        '''
+main(x) {
+  switch (x) {
+    case label: ////
+  }
+}
+''',
+        (s) => _after(s, 'label: '));
+  }
+
+  test_defaultNoColon() async {
+    await _prepareCompletion(
+        'default',
+        '''
+main(x) {
+  switch (x) {
+    default
+  }
+}
+''',
+        atEnd: true);
+    _assertHasChange(
+        'Complete switch-statement',
+        '''
+main(x) {
+  switch (x) {
+    default: ////
+  }
+}
+''',
+        (s) => _after(s, 'default: '));
+  }
+
   test_emptyCondition() async {
     await _prepareCompletion(
         'switch',
         '''
 main() {
   switch ()
 }
 ''',
         atEnd: true);
     _assertHasChange(
@@ skipping 308 matching lines @@
         '''
 main() {
   while () {
     ////
   }
 }
 ''',
         (s) => _after(s, 'while ('));
   }
 }