Fix analysis errors, warnings, and hints.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1184763005.

pkgs/watcher/lib/src/directory_watcher/linux.dart

diff --git a/pkgs/watcher/lib/src/directory_watcher/linux.dart b/pkgs/watcher/lib/src/directory_watcher/linux.dart
index 870faa7..04d88e6 100644
--- a/pkgs/watcher/lib/src/directory_watcher/linux.dart
+++ b/pkgs/watcher/lib/src/directory_watcher/linux.dart
@@ -7,8 +7,6 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:stack_trace/stack_trace.dart';
-
 import '../utils.dart';
 import '../watch_event.dart';
 import 'resubscribable.dart';
@@ -58,13 +56,13 @@
   _LinuxDirectoryWatcher(String directory)
       : directory = directory {
     // Batch the inotify changes together so that we can dedup events.
-    var innerStream = Chain.track(new Directory(directory).watch())
+    var innerStream = new Directory(directory).watch()
         .transform(new BatchedStreamTransformer<FileSystemEvent>());
     _listen(innerStream, _onBatch,
         onError: _eventsController.addError,
         onDone: _onDone);
 
-    _listen(Chain.track(new Directory(directory).list()), (entity) {
+    _listen(new Directory(directory).list(), (entity) {
       _entries[entity.path] = new _EntryState(entity is Directory);
       if (entity is! Directory) return;
       _watchSubdir(entity.path);
@@ -159,7 +157,7 @@
     // event for every new file.
     watcher.ready.then((_) {
       if (!isReady || _eventsController.isClosed) return;
-      _listen(Chain.track(new Directory(path).list(recursive: true)), (entry) {
+      _listen(new Directory(path).list(recursive: true), (entry) {
         if (entry is Directory) return;
         _eventsController.add(new WatchEvent(ChangeType.ADD, entry.path));
       }, onError: (error, stackTrace) {

pkgs/watcher/lib/src/directory_watcher/mac_os.dart

diff --git a/pkgs/watcher/lib/src/directory_watcher/mac_os.dart b/pkgs/watcher/lib/src/directory_watcher/mac_os.dart
index 89ac905..f3de727 100644
--- a/pkgs/watcher/lib/src/directory_watcher/mac_os.dart
+++ b/pkgs/watcher/lib/src/directory_watcher/mac_os.dart
@@ -7,8 +7,6 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:stack_trace/stack_trace.dart';
-
 import '../constructable_file_system_event.dart';
 import '../path_set.dart';
 import '../utils.dart';
@@ -136,7 +134,7 @@
           if (_files.containsDir(path)) continue;
 
           var subscription;
-          subscription = Chain.track(new Directory(path).list(recursive: true))
+          subscription = new Directory(path).list(recursive: true)
               .listen((entity) {
             if (entity is Directory) return;
             if (_files.contains(path)) return;
@@ -273,7 +271,7 @@
       case FileSystemEvent.MODIFY:
         return new ConstructableFileSystemModifyEvent(
             batch.first.path, isDir, false);
-      default: assert(false);
+      default: throw 'unreachable';
     }
   }
 
@@ -343,8 +341,7 @@
   /// Start or restart the underlying [Directory.watch] stream.
   void _startWatch() {
     // Batch the FSEvent changes together so that we can dedup events.
-    var innerStream =
-        Chain.track(new Directory(directory).watch(recursive: true))
+    var innerStream = new Directory(directory).watch(recursive: true)
         .transform(new BatchedStreamTransformer<FileSystemEvent>());
     _watchSubscription = innerStream.listen(_onBatch,
         onError: _eventsController.addError,
@@ -359,7 +356,7 @@
 
     _files.clear();
     var completer = new Completer();
-    var stream = Chain.track(new Directory(directory).list(recursive: true));
+    var stream = new Directory(directory).list(recursive: true);
     _initialListSubscription = stream.listen((entity) {
       if (entity is! Directory) _files.add(entity.path);
     },

pkgs/watcher/lib/src/directory_watcher/polling.dart

diff --git a/pkgs/watcher/lib/src/directory_watcher/polling.dart b/pkgs/watcher/lib/src/directory_watcher/polling.dart
index 12a3245..144391f 100644
--- a/pkgs/watcher/lib/src/directory_watcher/polling.dart
+++ b/pkgs/watcher/lib/src/directory_watcher/polling.dart
@@ -7,8 +7,6 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:stack_trace/stack_trace.dart';
-
 import '../async_queue.dart';
 import '../stat.dart';
 import '../utils.dart';
@@ -105,7 +103,7 @@
       _filesToProcess.add(null);
     }
 
-    var stream = Chain.track(new Directory(directory).list(recursive: true));
+    var stream = new Directory(directory).list(recursive: true);
     _listSubscription = stream.listen((entity) {
       assert(!_events.isClosed);
 

pkgs/watcher/lib/src/directory_watcher/windows.dart

diff --git a/pkgs/watcher/lib/src/directory_watcher/windows.dart b/pkgs/watcher/lib/src/directory_watcher/windows.dart
index 4f41d33..bd17cf4 100644
--- a/pkgs/watcher/lib/src/directory_watcher/windows.dart
+++ b/pkgs/watcher/lib/src/directory_watcher/windows.dart
@@ -10,7 +10,6 @@
 import 'dart:io';

 

 import 'package:path/path.dart' as p;

-import 'package:stack_trace/stack_trace.dart';

 

 import '../constructable_file_system_event.dart';

 import '../path_set.dart';

@@ -117,8 +116,7 @@
     var parent = p.dirname(absoluteDir);

     // Check if [directory] is already the root directory.

     if (FileSystemEntity.identicalSync(parent, directory)) return;

-    var parentStream = Chain.track(

-        new Directory(parent).watch(recursive: false));

+    var parentStream = new Directory(parent).watch(recursive: false);

     _parentWatchSubscription = parentStream.listen((event) {

       // Only look at events for 'directory'.

       if (p.basename(event.path) != p.basename(absoluteDir)) return;

@@ -159,7 +157,6 @@
   /// The callback that's run when [Directory.watch] emits a batch of events.

   void _onBatch(List<FileSystemEvent> batch) {

     _sortEvents(batch).forEach((path, events) {

-      var relativePath = p.relative(path, from: directory);

 

       var canonicalEvent = _canonicalEvent(events);

       events = canonicalEvent == null ?

@@ -177,7 +174,7 @@
 

           if (_files.containsDir(path)) continue;

 

-          var stream = Chain.track(new Directory(path).list(recursive: true));

+          var stream = new Directory(path).list(recursive: true);

           var sub;

           sub = stream.listen((entity) {

             if (entity is Directory) return;

@@ -262,7 +259,6 @@
 

     var type = batch.first.type;

     var isDir = batch.first.isDirectory;

-    var hadModifyEvent = false;

 

     for (var event in batch.skip(1)) {

       // If one event reports that the file is a directory and another event

@@ -273,10 +269,7 @@
       // safely assume the file was modified after a CREATE or before the

       // REMOVE; otherwise there will also be a REMOVE or CREATE event

       // (respectively) that will be contradictory.

-      if (event is FileSystemModifyEvent) {

-        hadModifyEvent = true;

-        continue;

-      }

+      if (event is FileSystemModifyEvent) continue;

       assert(event is FileSystemCreateEvent ||

              event is FileSystemDeleteEvent ||

              event is FileSystemMoveEvent);

@@ -305,7 +298,7 @@
             batch.first.path, isDir, false);

       case FileSystemEvent.MOVE:

         return null;

-      default: assert(false);

+      default: throw 'unreachable';

     }

   }

 

@@ -367,8 +360,7 @@
   /// Start or restart the underlying [Directory.watch] stream.

   void _startWatch() {

     // Batch the events together so that we can dedup events.

-    var innerStream =

-        Chain.track(new Directory(directory).watch(recursive: true));

+    var innerStream = new Directory(directory).watch(recursive: true);

     _watchSubscription = innerStream.listen(_onEvent,

         onError: _eventsController.addError,

         onDone: _onDone);

@@ -382,7 +374,7 @@
 

     _files.clear();

     var completer = new Completer();

-    var stream = Chain.track(new Directory(directory).list(recursive: true));

+    var stream = new Directory(directory).list(recursive: true);

     void handleEntity(entity) {

       if (entity is! Directory) _files.add(entity.path);

     }

pkgs/watcher/lib/src/stat.dart

diff --git a/pkgs/watcher/lib/src/stat.dart b/pkgs/watcher/lib/src/stat.dart
index 166d789..d36eff3 100644
--- a/pkgs/watcher/lib/src/stat.dart
+++ b/pkgs/watcher/lib/src/stat.dart
@@ -7,8 +7,6 @@
 import 'dart:async';
 import 'dart:io';
 
-import 'package:stack_trace/stack_trace.dart';
-
 /// A function that takes a file path and returns the last modified time for
 /// the file at that path.
 typedef DateTime MockTimeCallback(String path);
@@ -31,5 +29,5 @@
     return new Future.value(_mockTimeCallback(path));
   }
 
-  return Chain.track(FileStat.stat(path)).then((stat) => stat.modified);
+  return FileStat.stat(path).then((stat) => stat.modified);
 }