Fixed strong mode errors and warnings reachable from lib/observe.dart

lib/transformer.dart

Index: lib/transformer.dart
diff --git a/lib/transformer.dart b/lib/transformer.dart
index 52b4987054c3fff64d27163f14bbd28ecd9ed6ae..20e8f1d6973ed40db7627e7a7ca5a7856dd390ba 100644
--- a/lib/transformer.dart
+++ b/lib/transformer.dart
@@ -133,9 +133,9 @@ bool _hasObservable(AnnotatedNode node) =>
 // that is expensive in analyzer, so it isn't feasible yet.
 bool _isObservableAnnotation(Annotation node) =>
     _isAnnotationContant(node, 'observable') ||
-        _isAnnotationContant(node, 'published') ||
-        _isAnnotationType(node, 'ObservableProperty') ||
-        _isAnnotationType(node, 'PublishedProperty');
+    _isAnnotationContant(node, 'published') ||
+    _isAnnotationType(node, 'ObservableProperty') ||
+    _isAnnotationType(node, 'PublishedProperty');
 
 bool _isAnnotationContant(Annotation m, String name) =>
     m.name.name == name && m.constructorName == null && m.arguments == null;
@@ -263,7 +263,6 @@ String _getOriginalCode(TextEditTransaction code, AstNode node) =>
 
 void _fixConstructor(ConstructorDeclaration ctor, TextEditTransaction code,
     Set<String> changedFields) {
-
   // Fix normal initializers
   for (var initializer in ctor.initializers) {
     if (initializer is ConstructorFieldInitializer) {
@@ -392,7 +391,10 @@ void _transformFields(SourceFile file, FieldDeclaration member,
     final end = _findFieldSeperator(field.endToken.next);
     if (end.type == TokenType.COMMA) code.edit(end.offset, end.end, ';');
 
-    code.edit(end.end, end.end, ' @reflectable set $name($type value) { '
+    code.edit(
+        end.end,
+        end.end,
+        ' @reflectable set $name($type value) { '
         '__\$$name = notifyPropertyChange(#$name, __\$$name, value); }');
   }
 }