samples/poppopwin: upgrade to first-class sample

samples/pop_pop_win/lib/src/canvas/game_root.dart

 part of ppw_canvas;
 
 class GameRoot extends GameManager {
   final Stage _stage;
   final CanvasElement _canvas;
   final GameElement _gameElement;
   final AffineTransform _gameElementTx;
 
   bool _frameRequested = false;
 
@@ skipping 41 matching lines @@
   void toggleTargetFlag() => _gameElement.toggleTargetFlag();
 
   Stream get targetChanged => _gameElement.targetChanged;
 
   void onGameStateChanged(GameState newState) {
     switch(newState) {
       case GameState.won:
         GameAudio.win();
         break;
     }
-    targetPlatform.trackAnalyticsEvent('game', newState.name, game.field.toString());
-  }
-
-  void onNewBestTime(int value) {
-    targetPlatform.trackAnalyticsEvent('game', 'record', game.field.toString(), value);
   }
 
   void _updateCanvasSize() {
     final windowSize = new Size(window.innerWidth, window.innerHeight);
 
     _canvas.width = min(windowSize.width, _gameElement.width).toInt();
     _canvas.height = min(windowSize.height, _gameElement.height).toInt();
 
     // now move it!
     final delta = new Vector(windowSize.width - _canvas.width,
@@ skipping 67 matching lines @@
   }
 
   void _mouseOutHandler(args) {
     _updateCursor(false);
   }
 
   void _updateCursor(bool showFinger) {
     _canvas.style.cursor = showFinger ? 'pointer' : 'inherit';
   }
 }