Tweak for escaping in instrumentation.

pkg/analyzer/test/instrumentation/instrumentation_test.dart

 // Copyright (c) 2015, 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.instrumentation;
 
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:unittest/unittest.dart';
 import '../reflective_tests.dart';
 
@@ skipping 20 matching lines @@
     assertNormal(server, InstrumentationService.TAG_ERROR, message);
   }
 
   void test_logError_withColon() {
     TestInstrumentationServer server = new TestInstrumentationServer();
     InstrumentationService service = new InstrumentationService(server);
     service.logError('Error:message');
     assertNormal(server, InstrumentationService.TAG_ERROR, 'Error::message');
   }
 
+  void test_logError_withLeadingColon() {
+    TestInstrumentationServer server = new TestInstrumentationServer();
+    InstrumentationService service = new InstrumentationService(server);
+    service.logError(':a:bb');
+    assertNormal(server, InstrumentationService.TAG_ERROR, '::a::bb');
+  }
+
   void test_logException_noTrace() {
     TestInstrumentationServer server = new TestInstrumentationServer();
     InstrumentationService service = new InstrumentationService(server);
     String message = 'exceptionMessage';
     service.logException(message, null);
     assertNormal(server, InstrumentationService.TAG_EXCEPTION, '$message:null');
   }
 
   void test_logNotification() {
     TestInstrumentationServer server = new TestInstrumentationServer();
@@ skipping 32 matching lines @@
   @override
   void logWithPriority(String message) {
     priorityChannel.writeln(message);
   }
 
   @override
   void shutdown() {
     // Ignored
   }
 }