pkg/test: Resolve a number of analyzer warnings

lib/src/runner/browser/content_shell.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:async';
 import 'dart:convert';
 import 'dart:io';
 
 import '../../util/io.dart';
 import '../../utils.dart';
@@ skipping 23 matching lines @@
       if (executable == null) executable = _defaultExecutable();
 
       var tryPort = ([int port]) async {
         var args = ["--dump-render-tree", url.toString()];
         if (port != null) args.add("--remote-debugging-port=$port");
 
         var process = await Process.start(executable, args,
             environment: {"DART_FLAGS": "--checked"});
 
         if (debug) {
-          observatoryCompleter.complete(lineSplitter.bind(process.stdout)
+          observatoryCompleter.complete(transformUtf8ToLines(process.stdout)
               .map((line) {
             var match = _observatoryRegExp.firstMatch(line);
             if (match == null) return null;
             return Uri.parse(match[1]);
           }).where((uri) => uri != null).first);
         } else {
           observatoryCompleter.complete(null);
         }
 
-        var stderr = new StreamIterator(lineSplitter.bind(process.stderr));
+        var stderr = new StreamIterator(transformUtf8ToLines(process.stderr));
 
         // Before we can consider content_shell started successfully, we have to
         // make sure it's not expired and that the remote debugging port worked.
         // Any errors from this will always come before the "Running without
         // renderer sanxbox" message.
         while (await stderr.moveNext() &&
             !stderr.current.endsWith("Running without renderer sandbox")) {
           if (stderr.current == "[dartToStderr]: Dartium build has expired") {
             stderr.cancel();
             process.kill();
@@ skipping 33 matching lines @@
   /// Returns the full URL of the remote debugger for the host page.
   ///
   /// This takes the base remote debugger URL (which points to a browser-wide
   /// page) and uses its JSON API to find the resolved URL for debugging the
   /// host page.
   static Future<Uri> _getRemoteDebuggerUrl(Uri base) async {
     try {
       var client = new HttpClient();
       var request = await client.getUrl(base.resolve("/json/list"));
       var response = await request.close();
-      var json = await JSON.fuse(UTF8).decoder.bind(response).single;
+      var json = await JSON.fuse(UTF8).decoder.bind(response).single as List;
       return base.resolve(json.first["devtoolsFrontendUrl"]);
     } catch (_) {
       // If we fail to talk to the remote debugger protocol, give up and return
       // the raw URL rather than crashing.
       return base;
     }
   }
 
   ContentShell._(Future<Process> startBrowser(), this.observatoryUrl,
           this.remoteDebuggerUrl)
       : super(startBrowser);
 
   /// Return the default executable for the current operating system.
   static String _defaultExecutable() =>
       Platform.isWindows ? "content_shell.exe" : "content_shell";
 }