Format all dart dev compiler files

pkg/dev_compiler/lib/src/js_ast/type_printer.dart

Index: pkg/dev_compiler/lib/src/js_ast/type_printer.dart
diff --git a/pkg/dev_compiler/lib/src/js_ast/type_printer.dart b/pkg/dev_compiler/lib/src/js_ast/type_printer.dart
index db720bafc215c655d3df0a623c22818e3d3d6abe..35e7be6379cc56a07777da85954fc397387cf662 100644
--- a/pkg/dev_compiler/lib/src/js_ast/type_printer.dart
+++ b/pkg/dev_compiler/lib/src/js_ast/type_printer.dart
@@ -38,7 +38,6 @@ abstract class _TypePrinterBase implements TypeRefVisitor {
 }
 
 abstract class TypeScriptTypePrinter extends _TypePrinterBase {
-
   void _outTypeAnnotation(TypeRef type) {
     if (type is OptionalTypeRef) {
       out("?: ");
@@ -158,7 +157,8 @@ class ClosureTypePrinter extends _TypePrinterBase implements NodeVisitor {
     }
   }
 
-  @override toString() => _buffer.toString();
+  @override
+  toString() => _buffer.toString();
 
   @override
   visitArrayTypeRef(ArrayTypeRef node) {