Rework error handling in the service protocol and in Observatory.

runtime/observatory/lib/src/elements/io_view.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.
 
 library io_view_element;
 
 import 'dart:async';
 import 'observatory_element.dart';
 import 'service_ref.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
 @CustomTag('io-view')
 class IOViewElement extends ObservatoryElement {
   @published ServiceMap io;
 
   IOViewElement.created() : super.created();
 
-  void refresh(var done) {
-    io.reload().whenComplete(done);
+  Future refresh() {
+    return io.reload();
   }
 }
 
 @CustomTag('io-ref')
 class IORefElement extends ServiceRefElement {
   IORefElement.created() : super.created();
 }
 
 @CustomTag('io-http-server-list-view')
 class IOHttpServerListViewElement extends ObservatoryElement {
   @published ServiceMap list;
 
   IOHttpServerListViewElement.created() : super.created();
 
-  void refresh(var done) {
-    list.reload().whenComplete(done);
+  Future refresh() {
+    return list.reload();
   }
 }
 
 @CustomTag('io-http-server-ref')
 class IOHttpServerRefElement extends ServiceRefElement {
   IOHttpServerRefElement.created() : super.created();
 }
 
 @CustomTag('io-http-server-view')
 class IOHttpServerViewElement extends ObservatoryElement {
   // TODO(ajohnsen): Create a HttpServer object.
   @published ServiceMap httpServer;
   Timer _updateTimer;
 
   IOHttpServerViewElement.created() : super.created();
 
-  void refresh(var done) {
-    httpServer.reload().whenComplete(done);
+  Future refresh() {
+    return httpServer.reload();
   }
 
   void _updateHttpServer() {
-    refresh(() {
+    refresh().then((_) {
       if (_updateTimer != null) {
         _updateTimer = new Timer(new Duration(seconds: 1), _updateHttpServer);
       }
     });
   }
 
   @override
   void attached() {
     super.attached();
     // Start a timer to update the isolate summary once a second.
@@ skipping 10 matching lines @@
   }
 }
 
 @CustomTag('io-http-server-connection-view')
 class IOHttpServerConnectionViewElement extends ObservatoryElement {
   @published ServiceMap connection;
   Timer _updateTimer;
 
   IOHttpServerConnectionViewElement.created() : super.created();
 
-  void refresh(var done) {
-    connection.reload().whenComplete(done);
+  Future refresh() {
+    return connection.reload();
   }
 
   void _updateHttpServer() {
-    refresh(() {
+    refresh().then((_) {
       if (_updateTimer != null) {
         _updateTimer = new Timer(new Duration(seconds: 1), _updateHttpServer);
       }
     });
   }
 
   @override
   void attached() {
     super.attached();
     // Start a timer to update the isolate summary once a second.
@@ skipping 19 matching lines @@
 class IOSocketRefElement extends ServiceRefElement {
   IOSocketRefElement.created() : super.created();
 }
 
 @CustomTag('io-socket-list-view')
 class IOSocketListViewElement extends ObservatoryElement {
   @published ServiceMap list;
 
   IOSocketListViewElement.created() : super.created();
 
-  void refresh(var done) {
-    list.reload().whenComplete(done);
+  Future refresh() {
+    return list.reload();
   }
 }
 
 @CustomTag('io-socket-view')
 class IOSocketViewElement extends ObservatoryElement {
   @published Socket socket;
 
   IOSocketViewElement.created() : super.created();
 
-  void refresh(var done) {
-    socket.reload().whenComplete(done);
+  Future refresh() {
+    return socket.reload();
   }
 }
 
 @CustomTag('io-web-socket-ref')
 class IOWebSocketRefElement extends ServiceRefElement {
   IOWebSocketRefElement.created() : super.created();
 }
 
 @CustomTag('io-web-socket-list-view')
 class IOWebSocketListViewElement extends ObservatoryElement {
   @published ServiceMap list;
 
   IOWebSocketListViewElement.created() : super.created();
 
-  void refresh(var done) {
-    list.reload().whenComplete(done);
+  Future refresh() {
+    return list.reload();
   }
 }
 
 @CustomTag('io-web-socket-view')
 class IOWebSocketViewElement extends ObservatoryElement {
   @published ServiceMap webSocket;
 
   IOWebSocketViewElement.created() : super.created();
 
-  void refresh(var done) {
-    webSocket.reload().whenComplete(done);
+  Future refresh() {
+    return webSocket.reload();
   }
 }
 
 @CustomTag('io-random-access-file-list-view')
 class IORandomAccessFileListViewElement extends ObservatoryElement {
   @published ServiceMap list;
 
   IORandomAccessFileListViewElement.created() : super.created();
 
-  void refresh(var done) {
-    list.reload().whenComplete(done);
+  Future refresh() {
+    return list.reload();
   }
 }
 
 @CustomTag('io-random-access-file-ref')
 class IORandomAccessFileRefElement extends ServiceRefElement {
   IORandomAccessFileRefElement.created() : super.created();
 }
 
 @CustomTag('io-random-access-file-view')
 class IORandomAccessFileViewElement extends ObservatoryElement {
   // TODO(ajohnsen): Create a RandomAccessFile object.
   @published ServiceMap file;
   Timer _updateTimer;
 
   IORandomAccessFileViewElement.created() : super.created();
 
-  void refresh(var done) {
-    file.reload().whenComplete(done);
+  Future refresh() {
+    return file.reload();
   }
 
   void _updateFile() {
-    refresh(() {
+    refresh().then((_) {
       if (_updateTimer != null) {
         _updateTimer = new Timer(new Duration(seconds: 1), _updateFile);
       }
-    });
+    }).catchError(app.handleException);
   }
 
   @override
   void attached() {
     super.attached();
     // Start a timer to update the isolate summary once a second.
     _updateTimer = new Timer(new Duration(seconds: 1), _updateFile);
   }
 
   @override
   void detached() {
     super.detached();
     if (_updateTimer != null) {
       _updateTimer.cancel();
       _updateTimer = null;
     }
   }
 }
 
 @CustomTag('io-process-list-view')
 class IOProcessListViewElement extends ObservatoryElement {
   @published ServiceMap list;
 
   IOProcessListViewElement.created() : super.created();
 
-  void refresh(var done) {
-    list.reload().whenComplete(done);
+  Future refresh() {
+    return list.reload();
   }
 }
 
 @CustomTag('io-process-ref')
 class IOProcessRefElement extends ServiceRefElement {
   // Only display the process name when small is set.
   @published bool small = false;
   IOProcessRefElement.created() : super.created();
 }
 
 @CustomTag('io-process-view')
 class IOProcessViewElement extends ObservatoryElement {
   // TODO(ajohnsen): Create a Process object.
   @published ServiceMap process;
   Timer _updateTimer;
 
   IOProcessViewElement.created() : super.created();
 
-  void refresh(var done) {
-    process.reload().whenComplete(done);
+  Future refresh() {
+    return process.reload();
   }
 
   void _updateFile() {
-    refresh(() {
+    refresh().then((_) {
       if (_updateTimer != null) {
         _updateTimer = new Timer(new Duration(seconds: 1), _updateFile);
       }
-    });
+    }).catchError(app.handleException);
   }
 
   @override
   void attached() {
     super.attached();
     // Start a timer to update the isolate summary once a second.
     _updateTimer = new Timer(new Duration(seconds: 1), _updateFile);
   }
 
   @override
   void detached() {
     super.detached();
     if (_updateTimer != null) {
       _updateTimer.cancel();
       _updateTimer = null;
     }
   }
 }