send debug events for flutter lifecycle events (#3903)

* send debug events for flutter lifecycle events

* remove the route event

packages/flutter/lib/src/foundation/binding.dart

@@ -56,6 +56,8 @@ abstract class BindingBase {
     initServiceExtensions();
     assert(_debugServiceExtensionsRegistered);
 
+    developer.postEvent('Flutter.FrameworkInitialization', <String, dynamic>{});
+
     developer.Timeline.finishSync();
   }
 

packages/flutter/lib/src/widgets/binding.dart

@@ -208,6 +208,7 @@ abstract class WidgetsBinding extends BindingBase implements GestureBinding, Ren
     if (_needToReportFirstFrame) {
       if (_thisFrameWasUseful) {
         developer.Timeline.instantSync('Widgets completed first useful frame');
+        developer.postEvent('Flutter.FirstFrame', <String, dynamic>{});
         _needToReportFirstFrame = false;
       } else {
         _thisFrameWasUseful = true;