Converted Observatory logging-page element

runtime/observatory/lib/src/app/page.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of app;
 
 final _allocationProfileRepository = new AllocationProfileRepository();
 final _breakpointRepository = new BreakpointRepository();
 final _classSampleProfileRepository = new ClassSampleProfileRepository();
 final _classRepository = new ClassRepository();
@@ skipping 626 matching lines @@
     });
   }
 
   void onInstall() {
     if (element == null) {
       element = container;
     }
   }
 }
 
+class LoggingPage extends MatchingPage {
+  LoggingPage(app) : super('logging', app);
 
-class LoggingPage extends SimplePage {
-  LoggingPage(app) : super('logging', 'logging-page', app);
+  final DivElement container = new DivElement();
+
+  @override
+  void onInstall() {
+    element = container;
+    container.children = const [];
+    app.startLoggingEventListener();
+  }
+
+  @override
+  void onUninstall() {
+    app.stopLoggingEventListener();
+  }
 
   void _visit(Uri uri) {
-    super._visit(uri);
+    assert(element != null);
+    assert(canVisit(uri));
     getIsolate(uri).then((isolate) {
-      if (element != null) {
-        /// Update the page.
-        LoggingPageElement page = element;
-        page.isolate = isolate;
-      }
+      container.children = [
+        new LoggingPageElement(app.vm, isolate, app.events,
+                               app.notifications, queue: app.queue)
+      ];
     });
   }
 }
 
 class ErrorViewPage extends Page {
   ErrorViewPage(app) : super(app);
 
   void onInstall() {
     element = new ErrorViewElement(app.notifications,
                                    app.lastErrorOrException as DartError,
@@ skipping 123 matching lines @@
     assert(element != null);
   }
 
   void _visit(Uri uri) {
     assert(element != null);
     assert(canVisit(uri));
   }
 
   bool canVisit(Uri uri) => uri.path == 'timeline';
 }