Rework error handling in the service protocol and in Observatory.

runtime/observatory/lib/src/elements/heap_profile.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 heap_profile_element;
 
+import 'dart:async';
 import 'dart:html';
 import 'observatory_element.dart';
 import 'package:observatory/app.dart';
 import 'package:observatory/service.dart';
 import 'package:observatory/elements.dart';
 import 'package:polymer/polymer.dart';
 
 class ClassSortedTable extends SortedTable {
 
   ClassSortedTable(columns) : super(columns);
@@ skipping 75 matching lines @@
         shadowRoot.querySelector('#newPieChart'));
     _oldPieChart = new Chart('PieChart',
         shadowRoot.querySelector('#oldPieChart'));
     _classTableBody = shadowRoot.querySelector('#classTableBody');
     _subscription = app.vm.events.stream.where(
         (event) => event.isolate == isolate).listen(_onEvent);
   }
 
   @override
   void detached() {
-    _subscription.cancel((){});
+    _subscription.cancel();
     super.detached();
   }
   
   // Keep at most one outstanding auto-refresh RPC.
   bool refreshAutoPending = false;
   bool refreshAutoQueued = false;
   
   void _onEvent(ServiceEvent event) {
     if (autoRefresh && event.eventType == 'GC') {
       if (!refreshAutoPending) {
         refreshAuto();
       } else {
         // Remember to refresh once more, to ensure latest profile.
         refreshAutoQueued = true;
       }
     }
   }
 
   void refreshAuto() {
     refreshAutoPending = true;
     refreshAutoQueued = false;
-    refresh(() {
+    refresh().then((_) {
       refreshAutoPending = false;
       // Keep refreshing if at least one GC event was received while waiting.
       if (refreshAutoQueued) {
         refreshAuto();
       }
-    });
+    }).catchError(app.handleException);
   }
 
   void _updatePieCharts() {
     assert(profile != null);
     _newPieDataTable.clearRows();
     _newPieDataTable.addRow(['Used', isolate.newSpace.used]);
     _newPieDataTable.addRow(['Free',
         isolate.newSpace.capacity - isolate.newSpace.used]);
     _newPieDataTable.addRow(['External', isolate.newSpace.external]);
     _oldPieDataTable.clearRows();
@@ skipping 136 matching lines @@
       classTable.sort();
       _updateClassTableInDom();
     }
   }
 
   void isolateChanged(oldValue) {
     if (isolate == null) {
       profile = null;
       return;
     }
-    isolate.invokeRpc('_getAllocationProfile', {}).then(_update);
+    isolate.invokeRpc('_getAllocationProfile', {})
+      .then(_update)
+      .catchError(app.handleException);
   }
 
-  void refresh(var done) {
+  Future refresh() {
     if (isolate == null) {
-      return;
+      return new Future.value(null);
     }
-    isolate.invokeRpc('_getAllocationProfile', {})
-        .then(_update).whenComplete(done);
+    return isolate.invokeRpc('_getAllocationProfile', {})
+        .then(_update);
   }
 
-  void refreshGC(var done) {
+  Future refreshGC() {
     if (isolate == null) {
-      return;
+      return new Future.value(null);
     }
-    isolate.invokeRpc('_getAllocationProfile', { 'gc': 'full' })
-        .then(_update).whenComplete(done);
+    return isolate.invokeRpc('_getAllocationProfile', { 'gc': 'full' })
+        .then(_update);
   }
 
-  void resetAccumulator(var done) {
+  Future resetAccumulator() {
     if (isolate == null) {
-      return;
+      return new Future.value(null);
     }
-    isolate.invokeRpc('_getAllocationProfile', { 'reset': 'true' })
-        .then(_update).whenComplete(done);
+    return isolate.invokeRpc('_getAllocationProfile', { 'reset': 'true' })
+        .then(_update);
   }
 
   void _update(ServiceMap newProfile) {
     profile = newProfile;
   }
 
   void profileChanged(oldValue) {
     if (profile == null) {
       return;
     }
@@ skipping 36 matching lines @@
   }
 
   @observable String formattedTotalCollectionTime(bool newSpace) {
     if (profile == null) {
       return '';
     }
     var heap = newSpace ? isolate.newSpace : isolate.oldSpace;
     return '${Utils.formatSeconds(heap.totalCollectionTimeInSeconds)} secs';
   }
 }