anchor.diff:  
   import 'package:angular/angular.dart';
   import 'package:angular_forms/angular_forms.dart';
  +import 'package:angular_components/focus/focus.dart';
   import 'package:angular_components/glyph/glyph.dart';
   import 'package:angular_components/material_ripple/material_ripple.dart';
   import 'package:angular_components/model/ui/icon.dart';
  
positive.code:     styleUrls: const ['material_checkbox.scss.css'],
      changeDetection: ChangeDetectionStrategy.OnPush,
      visibility: Visibility.local)
  class MaterialCheckboxComponent implements ControlValueAccessor {
    final ChangeDetectorRef _changeDetector;
    final HtmlElement _root;
    final String _defaultTabIndex;
  
negative.code:     }
    }
  
    @override
    void focus() {
      if (disabled) return;
  
      // Set to true so that the focus indicator is rendered.
      _isKeyboardEvent = true;
  
      _root.focus();
    }
  
    // Capture keyup when we are the target of event.
    void handleKeyUp(KeyboardEvent event) {
      if (event.target != _root) return;
  