Address Pull Request feedback

(optional param default value + newlines)

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -674,6 +674,7 @@ class RenderIgnorePointer extends RenderProxyBox {
   RenderIgnorePointer({ RenderBox child, bool ignoring: true }) : super(child);
 
   bool ignoring;
+
   bool hitTest(HitTestResult result, { Point position }) {
     return ignoring ? false : super.hitTest(result, position: position);
   }

packages/flutter/lib/src/widgets/basic.dart

@@ -899,10 +899,11 @@ class WidgetToRenderBoxAdapter extends LeafRenderObjectWrapper {
 // EVENT HANDLING
 
 class IgnorePointer extends OneChildRenderObjectWrapper {
-  IgnorePointer({ Key key, Widget child, this.ignoring })
+  IgnorePointer({ Key key, Widget child, this.ignoring: true })
     : super(key: key, child: child);
 
   final bool ignoring;
+
   RenderIgnorePointer createNode() => new RenderIgnorePointer(ignoring: ignoring);
   RenderIgnorePointer get renderObject => super.renderObject;