feat(platform): cordova pause/resume events

ionic/platform/platform.ts

@@ -290,25 +290,39 @@ export class Platform {
   // called by engines (the browser)that do not provide them
 
   /**
-  * @private
+  * The `exitApp` method is useful when running from a native platform,
+  * such as Cordova. This adds the ability to place the Cordova app
+  * in the background.
   */
   exitApp() {}
 
   // Events meant to be triggered by the engine
   // **********************************************
 
   /**
-  * @private
+  * The back button event is emitted when the user presses the native
+  * platform's back button, also referred to as the "hardware" back button.
+  * This event is only emitted within Cordova apps running on Android and
+  * Windows platforms. This event is not fired on iOS since iOS doesn't come
+  * with a hardware back button in the same sense an Android or Windows device
+  * does. It's important to note that this event does not emit when the Ionic
+  * app's back button within the navbar is clicked, but this event is only
+  * referencing the platform's hardward back button.
   */
   backButton: EventEmitter<any> = new EventEmitter();
 
   /**
-  * @private
+  * The pause event emits when the native platform puts the application
+  * into the background, typically when the user switches to a different
+  * application. This event would emit when a Cordova app is put into
+  * the background, however, it would not fire on a standard web browser.
   */
   pause: EventEmitter<any> = new EventEmitter();
 
   /**
-  * @private
+  * The resume event emits when the native platform pulls the application
+  * out from the background. This event would emit when a Cordova app comes
+  * out from the background, however, it would not fire on a standard web browser.
   */
   resume: EventEmitter<any> = new EventEmitter();
 

ionic/platform/registry.ts

@@ -179,12 +179,12 @@ Platform.register({
           doc.addEventListener('backbutton', function() {
             p.backButton.emit(null);
           });
-          // doc.addEventListener('pause', function() {
-          //   p.pause.emit(null);
-          // });
-          // doc.addEventListener('resume', function() {
-          //   p.resume.emit(null);
-          // });
+          doc.addEventListener('pause', function() {
+            p.pause.emit(null);
+          });
+          doc.addEventListener('resume', function() {
+            p.resume.emit(null);
+          });
 
           // cordova has fully loaded and we've added listeners
           p.triggerReady();