Random cleanup of various Dart things in our tree.

sky/sdk/lib/mojo/asset_bundle.dart

 // 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.
 
 import 'dart:async';
 import 'dart:sky' as sky;
-import 'dart:typed_data';
 
 import 'package:mojo/core.dart' as core;
 import 'package:mojom/mojo/asset_bundle/asset_bundle.mojom.dart';
 
 import 'shell.dart' as shell;
 import 'net/fetch.dart';
 
 Future<sky.Image> _decodeImage(core.MojoDataPipeConsumer assetData) {
   Completer<sky.Image> completer = new Completer();
   new sky.ImageDecoder(assetData.handle.h, completer.complete);
@@ skipping 21 matching lines @@
   core.MojoDataPipeConsumer bundleData = (await fetchUrl(url)).body;
 
   AssetUnpackerProxy unpacker = new AssetUnpackerProxy.unbound();
   shell.requestService("mojo:asset_bundle", unpacker);
   AssetBundleProxy bundle = new AssetBundleProxy.unbound();
   unpacker.ptr.unpackZipStream(bundleData, bundle);
   unpacker.close();
 
   return new AssetBundle(bundle);
 }