Nicer pretty printing of jsAst object literals.

sdk/lib/_internal/compiler/implementation/js/nodes.dart

Index: sdk/lib/_internal/compiler/implementation/js/nodes.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js/nodes.dart b/sdk/lib/_internal/compiler/implementation/js/nodes.dart
index 5335faec6d74f3d6152411ad8c4c92ed57ed1f37..afc27dec1cdf8bc4dd560d9748bb45814538936e 100644
--- a/sdk/lib/_internal/compiler/implementation/js/nodes.dart
+++ b/sdk/lib/_internal/compiler/implementation/js/nodes.dart
@@ -925,8 +925,16 @@ class ArrayElement extends Node {
 
 class ObjectInitializer extends Expression {
   List<Property> properties;
+  bool isOneLiner;
 
-  ObjectInitializer(this.properties);
+  /**
+   * Constructs a new object-initializer containing the given [properties].
+   *
+   * [isOneLiner] describes the behaviour when pretty-printing (non-minified).
+   * If true print all properties on the same line.
+   * If false print each property on a seperate line.
+   */
+  ObjectInitializer(this.properties, {this.isOneLiner: true});
 
   accept(NodeVisitor visitor) => visitor.visitObjectInitializer(this);