Dart: Remove unused library and example

examples/dart/traced_application/lib/main.dart

-#!mojo mojo:dart_content_handler
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// This example application illustrates how to use Mojo Tracing from Dart code.
-//
-// To run this app:
-// mojo/devtools/common/mojo_run --trace-startup \
-//   https://core.mojoapps.io/examples/dart/traced_application/lib/main.dart
-//
-// This will produce a file called |mojo_shell.trace| that may be loaded
-// by Chrome's about:tracing.
-
-import 'dart:async';
-import 'dart:io';
-
-import 'package:common/tracing_helper.dart';
-import 'package:mojo/application.dart';
-import 'package:mojo/bindings.dart';
-import 'package:mojo/core.dart';
-
-class TestUsingTracingApp extends Application {
-  TracingHelper _tracing;
-  Timer _timer;
-
-  TestUsingTracingApp.fromHandle(MojoHandle handle) : super.fromHandle(handle);
-
-  void initialize(List<String> args, String url) {
-    // This sets up a connection between this application and the Mojo
-    // tracing service.
-    _tracing = new TracingHelper.fromApplication(
-        this, "example_traced_application", TraceSendTiming.AT_END);
-    _tracing.traceInstant("initialized", "traced_application");
-
-    // Now we schedule some random work just so we have something to trace.
-    _timer = new Timer.periodic(new Duration(seconds: 1), (t) => function1());
-
-    onError = (() {
-      if (_timer != null) {
-        _timer.cancel();
-      }
-    });
-  }
-
-  @override
-  void acceptConnection(String requestorUrl, String resolvedUrl,
-      ApplicationConnection connection) {
-    _tracing.traceInstant("connected", "traced_application");
-  }
-
-  Future function1() {
-    return _tracing.traceAsync("function1", "traced_application", () async {
-      await waitForMilliseconds(100);
-      await function2(42);
-      await waitForMilliseconds(100);
-    });
-  }
-
-  Future function2(int x) {
-    return _tracing.traceAsync("function2", "traced_application", () async {
-      await waitForMilliseconds(200);
-      assert(await identity(42) == 42);
-      assert(await fourtyTwo() == 42);
-      assert(await addOne(42) == 43);
-      await doNothing();
-    }, args: {"x": x});
-  }
-
-  Future identity(int x) {
-    return _tracing.traceAsync("identity", "traced_application", () async {
-      await waitForMilliseconds(10);
-      return x;
-    });
-  }
-
-  Future addOne(int x) {
-    return _tracing.traceAsync("add1", "traced_application", () async {
-      await waitForMilliseconds(10);
-      return x + 1;
-    }, args: {"x": x});
-  }
-
-  Future fourtyTwo() {
-    return _tracing.traceAsync("fourtyTwo", "traced_application", () async {
-      await waitForMilliseconds(10);
-      return 42;
-    });
-  }
-
-  Future doNothing() {
-    return _tracing.traceAsync("doNothing", "traced_application", () async {
-      await waitForMilliseconds(10);
-    });
-  }
-}
-
-Future waitForMilliseconds(int milliseconds) {
-  return new Future.delayed(new Duration(milliseconds: milliseconds), () {});
-}
-
-main(List args) {
-  MojoHandle appHandle = new MojoHandle(args[0]);
-  new TestUsingTracingApp.fromHandle(appHandle);
-}