Reland "Merge more Kernel infrastructure from kernel_sdk SDK fork."

runtime/lib/timeline.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.
 
-import 'dart:_internal';
-
 @patch bool _isDartStreamEnabled() native "Timeline_isDartStreamEnabled";
 
 @patch int _getTraceClock() native "Timeline_getTraceClock";
 
 @patch int _getThreadCpuClock() native "Timeline_getThreadCpuClock";
 
 @patch int _getNextAsyncId() native "Timeline_getNextAsyncId";
 
 @patch int _getIsolateNum() native "Timeline_getIsolateNum";
 
@@ skipping 10 matching lines @@
      int end,
      String category,
      String name,
      String argumentsAsJson) native "Timeline_reportCompleteEvent";
 
 @patch void _reportInstantEvent(
      int start,
      String category,
      String name,
      String argumentsAsJson) native "Timeline_reportInstantEvent";