Add lints from package:pedantic (dart-lang/watcher#66)

- Fix a control_flow_in_finally by removing the nested try/catch which
  was set up for ordering of behavior and instead check for a closed
  controller in both places.
- Fix a prefer_is_not_empty.

pkgs/watcher/analysis_options.yaml

diff --git a/pkgs/watcher/analysis_options.yaml b/pkgs/watcher/analysis_options.yaml
index 4c9f811..3155c7f 100644
--- a/pkgs/watcher/analysis_options.yaml
+++ b/pkgs/watcher/analysis_options.yaml
@@ -1,3 +1,4 @@
+include: package:pedantic/analysis_options.yaml
 analyzer:
   strong-mode:
     implicit-casts: false

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

diff --git a/pkgs/watcher/lib/src/file_watcher/polling.dart b/pkgs/watcher/lib/src/file_watcher/polling.dart
index 777038f..877031e 100644
--- a/pkgs/watcher/lib/src/file_watcher/polling.dart
+++ b/pkgs/watcher/lib/src/file_watcher/polling.dart
@@ -60,16 +60,14 @@
 
     DateTime modified;
     try {
-      try {
-        modified = await getModificationTime(path);
-      } finally {
-        if (_eventsController.isClosed) return;
-      }
+      modified = await getModificationTime(path);
     } on FileSystemException catch (error, stackTrace) {
-      _eventsController.addError(error, stackTrace);
-      close();
-      return;
+      if (!_eventsController.isClosed) {
+        _eventsController.addError(error, stackTrace);
+        await close();
+      }
     }
+    if (_eventsController.isClosed) return;
 
     if (_lastModified == modified) return;
 
@@ -84,8 +82,8 @@
     }
   }
 
-  void close() {
+  Future<void> close() async {
     _timer.cancel();
-    _eventsController.close();
+    await _eventsController.close();
   }
 }

pkgs/watcher/lib/src/path_set.dart

diff --git a/pkgs/watcher/lib/src/path_set.dart b/pkgs/watcher/lib/src/path_set.dart
index 9a2c03c..d6983ff 100644
--- a/pkgs/watcher/lib/src/path_set.dart
+++ b/pkgs/watcher/lib/src/path_set.dart
@@ -136,7 +136,7 @@
       if (entry == null) return false;
     }
 
-    return !entry.contents.isEmpty;
+    return entry.contents.isNotEmpty;
   }
 
   /// All of the paths explicitly added to this set.

pkgs/watcher/pubspec.yaml

diff --git a/pkgs/watcher/pubspec.yaml b/pkgs/watcher/pubspec.yaml
index 552b13a..c107856 100644
--- a/pkgs/watcher/pubspec.yaml
+++ b/pkgs/watcher/pubspec.yaml
@@ -16,5 +16,6 @@
 
 dev_dependencies:
   benchmark_harness: ^1.0.4
+  pedantic: ^1.1.0
   test: '>=0.12.42 <2.0.0'
   test_descriptor: ^1.0.0