Update charted to 0.4.8 and roll

packages/stack_trace/test/vm_test.dart

 // Copyright (c) 2013, 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.
 
 /// This file tests stack_trace's ability to parse live stack traces. It's a
 /// dual of dartium_test.dart, since method names can differ somewhat from
 /// platform to platform. No similar file exists for dart2js since the specific
 /// method names there are implementation details.
 @TestOn('vm')
 
 import 'package:path/path.dart' as path;
 import 'package:stack_trace/stack_trace.dart';
 import 'package:test/test.dart';
 
-String getStackTraceString() {
-  try {
-    throw '';
-  } catch (_, stackTrace) {
-    return stackTrace.toString();
-  }
-}
+// The name of this (trivial) function is verified as part of the test
+String getStackTraceString() => StackTrace.current.toString();
 
-StackTrace getStackTraceObject() {
-  try {
-    throw '';
-  } catch (_, stackTrace) {
-    return stackTrace;
-  }
-}
+// The name of this (trivial) function is verified as part of the test
+StackTrace getStackTraceObject() => StackTrace.current;
 
 Frame getCaller([int level]) {
   if (level == null) return new Frame.caller();
   return new Frame.caller(level);
 }
 
 Frame nestedGetCaller(int level) => getCaller(level);
 
 Trace getCurrentTrace([int level]) => new Trace.current(level);
 
@@ skipping 72 matching lines @@
 
     test('at level 2 returns the grandparent frame', () {
       expect(nestedGetCaller(2).member, equals('main.<fn>.<fn>'));
     });
 
     test('throws an ArgumentError for negative levels', () {
       expect(() => new Frame.caller(-1), throwsArgumentError);
     });
   });
 }