checked mode fix; add type annotation (#3737)

dev/dartdoc.dart

-#!/usr/bin/env dart
-
-// Copyright 2016 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:convert';
-import 'dart:io';
-
-// TODO (devoncarew): Remove this once the chromium bot is updated.
-Future<Null> main(List<String> args) async {
-  Process.runSync('pub', <String>['get'], workingDirectory: 'dev/tools');
-  Process process = await Process.start('dart', <String>['dartdoc.dart'],
-    workingDirectory: 'dev/tools');
-  process.stdout
-    .transform(UTF8.decoder)
-    .transform(const LineSplitter())
-    .listen(print);
-  process.stderr
-    .transform(UTF8.decoder)
-    .transform(const LineSplitter())
-    .listen(print);
-  exit(await process.exitCode);
-}

packages/flutter_markdown/lib/src/markdown_style_raw.dart

@@ -100,7 +100,7 @@ class MarkdownStyleRaw {
   Map<String, TextStyle> get styles => _styles;
 
   void _init() {
-    _styles = {
+    _styles = <String, TextStyle>{
       'a': a,
       'p': p,
       'li': p,

packages/flutter_tools/lib/src/runner/flutter_command_runner.dart

@@ -425,6 +425,7 @@ class FlutterCommandRunner extends CommandRunner {
       .listSync(followLinks: false)
       .expand((FileSystemEntity entity) {
         return entity is Directory ? _gatherProjectPaths(entity.path) : <String>[];
-      });
+      })
+      .toList();
   }
 }