edit pass on T3,4,5, updated images

src/site/docs/tutorials/indexeddb/examples/count_down/out/web/xcountdown.dart

+// Some things we need.
+import 'package:polymer/polymer.dart';
+import 'dart:html';
+import 'dart:async';
+import 'count_down.dart';
+
+@CustomTag('x-count-down')
+class CountDownComponent extends PolymerElement {
+  
+  // Observe errorMsg.
+  // It displays a message for the user.
+  @observable String get errorMsg => __$errorMsg; String __$errorMsg = ''; set errorMsg(String value) { __$errorMsg = notifyPropertyChange(#errorMsg, __$errorMsg, value); }
+
+  // These are bound to input elements.
+  @observable String get newMilestoneName => __$newMilestoneName; String __$newMilestoneName = "New Year's Day"; set newMilestoneName(String value) { __$newMilestoneName = notifyPropertyChange(#newMilestoneName, __$newMilestoneName, value); }
+  @observable String get newMilestoneDate => __$newMilestoneDate; String __$newMilestoneDate = '2014-01-01'; set newMilestoneDate(String value) { __$newMilestoneDate = notifyPropertyChange(#newMilestoneDate, __$newMilestoneDate, value); }
+  @observable String get newMilestoneTime => __$newMilestoneTime; String __$newMilestoneTime = '00:00:00'; set newMilestoneTime(String value) { __$newMilestoneTime = notifyPropertyChange(#newMilestoneTime, __$newMilestoneTime, value); }
+  
+  @observable MilestoneApp get appObj => __$appObj; MilestoneApp __$appObj = appObject; set appObj(MilestoneApp value) { __$appObj = notifyPropertyChange(#appObj, __$appObj, value); }
+  
+  /*
+   * Click handlers.
+   * NOTE: Minus - button handler is in xmilestone web component.
+   */
+  // Plus + button click handler.
+  void addMilestone(Event e, var detail, Node target) {
+    String str = newMilestoneDate + ' ' + newMilestoneTime;  
+    DateTime occursOn = DateTime.parse(str);
+
+    appObject.addMilestone(newMilestoneName, occursOn);
+  }
+
+  // Clear button click handler.
+  void clear(Event e, var detail, Node target) {
+    errorMsg = '';
+    appObject.clear();
+  }
+   
+  /*
+   * Life-cycle bizness
+   */
+  void inserted() {
+    appObject.start()
+      .catchError((e) {
+        ($['addbutton'] as ButtonElement).disabled = true;
+        ($['clearbutton'] as ButtonElement).disabled = true;
+
+        errorMsg = e.toString();
+      });
+  }
+  
+  void removed() {
+    appObject.stop();
+  }
+} // end class