Add 'FlushRealTimeEvents' to window.

sky/engine/core/dart/window.dart

@@ -121,6 +121,9 @@ class Window {
   /// [Scene]. For optimal performance, this should only be called in response
   /// to the [onBeginFrame] callback being invoked.
   void render(Scene scene) native "Window_render";
+
+  /// Flushes pending real-time events, executing their callbacks.
+  void flushRealTimeEvents() native "Scheduler_FlushRealTimeEvents";
 }
 
 /// The [Window] singleton.

sky/engine/core/window/window.cc

@@ -29,6 +29,11 @@ void Render(Dart_NativeArguments args) {
   DOMDartState::Current()->window()->client()->Render(scene);
 }
 
+
+void FlushRealTimeEvents(Dart_NativeArguments args) {
+  DOMDartState::Current()->window()->client()->FlushRealTimeEvents();
+}
+
 }  // namespace
 
 WindowClient::~WindowClient() {
@@ -140,6 +145,7 @@ void Window::RegisterNatives(DartLibraryNatives* natives) {
   natives->Register({
     { "Window_scheduleFrame", ScheduleFrame, 1, true },
     { "Window_render", Render, 2, true },
+    { "Scheduler_FlushRealTimeEvents", FlushRealTimeEvents, 1, true},
   });
 }
 

sky/engine/core/window/window.h

@@ -18,6 +18,7 @@ class DartLibraryNatives;
 class WindowClient {
  public:
   virtual void ScheduleFrame() = 0;
+  virtual void FlushRealTimeEvents() = 0;
   virtual void Render(Scene* scene) = 0;
 
  protected:

sky/engine/public/sky/sky_headless.cc

@@ -37,6 +37,9 @@ void SkyHeadless::RunFromSnapshotBuffer(const uint8_t* buffer, size_t size) {
 void SkyHeadless::ScheduleFrame() {
 }
 
+void SkyHeadless::FlushRealTimeEvents() {
+}
+
 void SkyHeadless::Render(Scene* scene) {
 }
 

sky/engine/public/sky/sky_headless.h

@@ -37,6 +37,7 @@ class SkyHeadless : public WindowClient {
 
  private:
   void ScheduleFrame() override;
+  void FlushRealTimeEvents() override;
   void Render(Scene* scene) override;
 
   std::unique_ptr<DartController> dart_controller_;

sky/engine/public/sky/sky_view.cc

@@ -100,6 +100,10 @@ void SkyView::ScheduleFrame() {
   client_->ScheduleFrame();
 }
 
+void SkyView::FlushRealTimeEvents() {
+  client_->FlushRealTimeEvents();
+}
+
 void SkyView::Render(Scene* scene) {
   layer_tree_ = scene->takeLayerTree();
 }

sky/engine/public/sky/sky_view.h

@@ -62,6 +62,7 @@ class SkyView : public WindowClient {
   Window* GetWindow();
 
   void ScheduleFrame() override;
+  void FlushRealTimeEvents() override;
   void Render(Scene* scene) override;
 
   SkyViewClient* client_;

sky/engine/public/sky/sky_view_client.h

@@ -16,6 +16,7 @@ namespace blink {
 class SkyViewClient {
  public:
   virtual void ScheduleFrame() = 0;
+  virtual void FlushRealTimeEvents() = 0;
   virtual void Render(std::unique_ptr<sky::compositor::LayerTree> layer_tree) = 0;
 
   virtual void DidCreateIsolate(Dart_Isolate isolate) = 0;

sky/shell/ui/animator.cc

@@ -50,6 +50,14 @@ void Animator::RequestFrame() {
   }
 }
 
+void Animator::FlushRealTimeEvents() {
+  if (outstanding_requests_ > 0)
+    rasterizer_.WaitForIncomingResponseWithTimeout(0);
+
+  if (engine_requested_frame_ && vsync_provider_)
+    vsync_provider_.WaitForIncomingResponseWithTimeout(0);
+}
+
 void Animator::Stop() {
   paused_ = true;
 }

sky/shell/ui/animator.h

@@ -19,6 +19,7 @@ class Animator {
   ~Animator();
 
   void RequestFrame();
+  void FlushRealTimeEvents();
 
   void Start();
   void Stop();

sky/shell/ui/engine.cc

@@ -280,6 +280,10 @@ void Engine::ScheduleFrame() {
   animator_->RequestFrame();
 }
 
+void Engine::FlushRealTimeEvents() {
+  animator_->FlushRealTimeEvents();
+}
+
 void Engine::Render(std::unique_ptr<compositor::LayerTree> layer_tree) {
 }
 

sky/shell/ui/engine.h

@@ -75,6 +75,7 @@ class Engine : public UIDelegate,
 
   // SkyViewClient methods:
   void ScheduleFrame() override;
+  void FlushRealTimeEvents() override;
   void Render(std::unique_ptr<compositor::LayerTree> layer_tree) override;
   void DidCreateIsolate(Dart_Isolate isolate) override;