Render without rendering rule

lib/ui/platform_dispatcher.dart

@@ -308,29 +308,6 @@ class PlatformDispatcher {
     _invoke(onMetricsChanged, _onMetricsChangedZone);
   }
 
-  // A debug-only variable that stores the [FlutterView]s for which
-  // [FlutterView.render] has already been called during the current
-  // [onBeginFrame]/[onDrawFrame] callback sequence.
-  //
-  // It is null outside the scope of those callbacks indicating that calls to
-  // [FlutterView.render] must be ignored. Furthermore, if a given [FlutterView]
-  // is already present in this set when its [FlutterView.render] is called
-  // again, that call must be ignored as a duplicate.
-  //
-  // Between [onBeginFrame] and [onDrawFrame] the properties value is
-  // temporarily stored in `_renderedViewsBetweenCallbacks` so that it survives
-  // the gap between the two callbacks.
-  //
-  // In release build, this variable is null, and therefore the calling rule is
-  // not enforced. This is because the check might hurt cold startup delay;
-  // see https://github.com/flutter/engine/pull/46919.
-  Set<FlutterView>? _debugRenderedViews;
-  // A debug-only variable that temporarily stores the `_renderedViews` value
-  // between `_beginFrame` and `_drawFrame`.
-  //
-  // In release build, this variable is null.
-  Set<FlutterView>? _debugRenderedViewsBetweenCallbacks;
-
   /// A callback invoked when any view begins a frame.
   ///
   /// A callback that is invoked to notify the application that it is an
@@ -351,26 +328,11 @@ class PlatformDispatcher {
 
   // Called from the engine, via hooks.dart
   void _beginFrame(int microseconds) {
-    assert(_debugRenderedViews == null);
-    assert(_debugRenderedViewsBetweenCallbacks == null);
-    assert(() {
-      _debugRenderedViews = <FlutterView>{};
-      return true;
-    }());
-
     _invoke1<Duration>(
       onBeginFrame,
       _onBeginFrameZone,
       Duration(microseconds: microseconds),
     );
-
-    assert(_debugRenderedViews != null);
-    assert(_debugRenderedViewsBetweenCallbacks == null);
-    assert(() {
-      _debugRenderedViewsBetweenCallbacks = _debugRenderedViews;
-      _debugRenderedViews = null;
-      return true;
-    }());
   }
 
   /// A callback that is invoked for each frame after [onBeginFrame] has
@@ -388,22 +350,7 @@ class PlatformDispatcher {
 
   // Called from the engine, via hooks.dart
   void _drawFrame() {
-    assert(_debugRenderedViews == null);
-    assert(_debugRenderedViewsBetweenCallbacks != null);
-    assert(() {
-      _debugRenderedViews = _debugRenderedViewsBetweenCallbacks;
-      _debugRenderedViewsBetweenCallbacks = null;
-      return true;
-    }());
-
     _invoke(onDrawFrame, _onDrawFrameZone);
-
-    assert(_debugRenderedViews != null);
-    assert(_debugRenderedViewsBetweenCallbacks == null);
-    assert(() {
-      _debugRenderedViews = null;
-      return true;
-    }());
   }
 
   /// A callback that is invoked when pointer data is available.

lib/ui/window.dart

@@ -372,18 +372,7 @@ class FlutterView {
   /// * [RendererBinding], the Flutter framework class which manages layout and
   ///   painting.
   void render(Scene scene, {Size? size}) {
-    // Duplicated calls or calls outside of onBeginFrame/onDrawFrame (indicated
-    // by _debugRenderedViews being null) are ignored. See _debugRenderedViews.
-    // TODO(dkwingsmt): We should change this skip into an assertion.
-    // https://github.com/flutter/flutter/issues/137073
-    bool validRender = true;
-    assert(() {
-      validRender = platformDispatcher._debugRenderedViews?.add(this) ?? false;
-      return true;
-    }());
-    if (validRender) {
-      _render(viewId, scene as _NativeScene, size?.width ?? physicalSize.width, size?.height ?? physicalSize.height);
-    }
+    _render(viewId, scene as _NativeScene, size?.width ?? physicalSize.width, size?.height ?? physicalSize.height);
   }
 
   @Native<Void Function(Int64, Pointer<Void>, Double, Double)>(symbol: 'PlatformConfigurationNativeApi::Render')

runtime/runtime_controller.cc

@@ -153,6 +153,10 @@ bool RuntimeController::RemoveView(int64_t view_id) {
   return false;
 }
 
+size_t RuntimeController::NumViews() const {
+  return platform_data_.viewport_metrics_for_views.size();
+}
+
 bool RuntimeController::SetViewportMetrics(int64_t view_id,
                                            const ViewportMetrics& metrics) {
   TRACE_EVENT0("flutter", "SetViewportMetrics");

runtime/runtime_controller.h

@@ -192,6 +192,11 @@ class RuntimeController : public PlatformConfigurationClient {
   ///
   bool RemoveView(int64_t view_id);
 
+  //----------------------------------------------------------------------------
+  /// @brief      Return the number of views registered.
+  ///
+  size_t NumViews() const;
+
   //----------------------------------------------------------------------------
   /// @brief      Forward the specified viewport metrics to the running isolate.
   ///             If the isolate is not running, these metrics will be saved and

shell/common/animator.cc

@@ -119,7 +119,9 @@ void Animator::BeginFrame(
 }
 
 void Animator::EndFrame() {
-  FML_CHECK(frame_timings_recorder_ != nullptr);
+  if (frame_timings_recorder_ == nullptr) {
+    return;
+  }
   if (!layer_trees_tasks_.empty()) {
     // The build is completed in OnAnimatorBeginFrame.
     frame_timings_recorder_->RecordBuildEnd(fml::TimePoint::Now());
@@ -179,10 +181,16 @@ void Animator::EndFrame() {
 void Animator::Render(int64_t view_id,
                       std::unique_ptr<flutter::LayerTree> layer_tree,
                       float device_pixel_ratio) {
-  FML_CHECK(frame_timings_recorder_ != nullptr);
-
   has_rendered_ = true;
 
+  if (!frame_timings_recorder_) {
+    // Framework can directly call render with a built scene.
+    frame_timings_recorder_ = std::make_unique<FrameTimingsRecorder>();
+    const fml::TimePoint placeholder_time = fml::TimePoint::Now();
+    frame_timings_recorder_->RecordVsync(placeholder_time, placeholder_time);
+    frame_timings_recorder_->RecordBuildStart(placeholder_time);
+  }
+
   TRACE_EVENT_WITH_FRAME_NUMBER(frame_timings_recorder_, "flutter",
                                 "Animator::Render", /*flow_id_count=*/0,
                                 /*flow_ids=*/nullptr);

shell/common/animator.h

@@ -89,14 +89,15 @@ class Animator final {
   // rendering.
   void EnqueueTraceFlowId(uint64_t trace_flow_id);
 
+  void EndFrame();
+
  private:
   // Animator's work during a vsync is split into two methods, BeginFrame and
   // EndFrame. The two methods should be called synchronously back-to-back to
   // avoid being interrupted by a regular vsync. The reason to split them is to
   // allow ShellTest::PumpOneFrame to insert a Render in between.
 
   void BeginFrame(std::unique_ptr<FrameTimingsRecorder> frame_timings_recorder);
-  void EndFrame();
 
   bool CanReuseLastLayerTrees();
 

shell/common/engine.cc

@@ -259,6 +259,7 @@ Engine::RunStatus Engine::Run(RunConfiguration configuration) {
 }
 
 void Engine::BeginFrame(fml::TimePoint frame_time, uint64_t frame_number) {
+  MarkAsEndOfFrame();
   runtime_controller_->BeginFrame(frame_time, frame_number);
 }
 
@@ -475,6 +476,23 @@ void Engine::Render(int64_t view_id,
   }
 
   animator_->Render(view_id, std::move(layer_tree), device_pixel_ratio);
+  rendered_views_during_frame_.insert(view_id);
+  SubmitFrameIfEndOfFrame();
+}
+
+void Engine::MarkAsEndOfFrame() {
+  rendered_views_during_frame_.clear();
+}
+
+void Engine::SubmitFrameIfEndOfFrame() {
+  if (!runtime_controller_) {
+    return;
+  }
+  if (rendered_views_during_frame_.size() != 0 &&
+      rendered_views_during_frame_.size() == runtime_controller_->NumViews()) {
+    animator_->EndFrame();
+    MarkAsEndOfFrame();
+  }
 }
 
 void Engine::UpdateSemantics(SemanticsNodeUpdates update,

shell/common/engine.h

@@ -1014,6 +1014,10 @@ class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
 
   bool GetAssetAsBuffer(const std::string& name, std::vector<uint8_t>* data);
 
+  void MarkAsEndOfFrame();
+
+  void SubmitFrameIfEndOfFrame();
+
   friend class testing::ShellTest;
 
   Engine::Delegate& delegate_;
@@ -1026,6 +1030,8 @@ class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
   // is destructed first.
   std::unique_ptr<PointerDataDispatcher> pointer_data_dispatcher_;
 
+  std::unordered_set<uint64_t> rendered_views_during_frame_;
+
   std::string last_entry_point_;
   std::string last_entry_point_library_;
   std::vector<std::string> last_entry_point_args_;