Canvas API. There are still a number of things to do:

runtime/embedders/openglui/common/dart_host.cc

 // Copyright (c) 2012, 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.
 
 #include "embedders/openglui/common/dart_host.h"
 
 #include <math.h>
 #include <unistd.h>
 
 #include "embedders/openglui/common/log.h"
@@ skipping 21 matching lines @@
     LOGI("Activating DartHost");
     if (graphics_handler_->Start() != 0) {
       return -1;
     }
     if (sound_handler_->Start() != 0) {
       return -1;
     }
     if (input_handler_->Start() != 0) {
       return -1;
     }
-    timer_->reset();
+    timer_->Reset();
     LOGI("Starting main isolate");
     int result = vm_glue_->StartMainIsolate();
     if (result != 0) {
       LOGE("startMainIsolate returned %d", result);
       return -1;
     }
     active_ = true;
-    vm_glue_->CallSetup();
+    return vm_glue_->CallSetup();
   }
   return 0;
 }
 
 void DartHost::OnDeactivate() {
   Deactivate();
 }
 
 void DartHost::Deactivate() {
   if (active_) {
     active_ = false;
     vm_glue_->FinishMainIsolate();
     LOGI("Deactivating DartHost");
     input_handler_->Stop();
     sound_handler_->Stop();
     graphics_handler_->Stop();
   }
 }
 
 int32_t DartHost::OnStep() {
-  timer_->update();
-  vm_glue_->CallUpdate();
-  if (graphics_handler_->Update() != 0) {
+  timer_->Update();
+  if (vm_glue_->CallUpdate() != 0 ||
+      graphics_handler_->Update() != 0) {
     return -1;
   }
   return 0;
 }
 
 void DartHost::OnStart() {
   LOGI("Starting DartHost");
 }
 
 void DartHost::OnResume() {
@@ skipping 33 matching lines @@
 }
 
 void DartHost::OnGainedFocus() {
   LOGI("DartHost gained focus");
 }
 
 void DartHost::OnLostFocus() {
   LOGI("DartHost lost focus");
 }