Change to scheduleWarmUpFrame and EndWarmUpFrame

lib/ui/dart_ui.cc

@@ -98,7 +98,7 @@ typedef CanvasPath Path;
   V(NativeStringAttribute::initSpellOutStringAttribute)            \
   V(PlatformConfigurationNativeApi::DefaultRouteName)              \
   V(PlatformConfigurationNativeApi::ScheduleFrame)                 \
-  V(PlatformConfigurationNativeApi::RequestWarmUpFrame)            \
+  V(PlatformConfigurationNativeApi::EndWarmUpFrame)                \
   V(PlatformConfigurationNativeApi::Render)                        \
   V(PlatformConfigurationNativeApi::UpdateSemantics)               \
   V(PlatformConfigurationNativeApi::SetNeedsReportTimings)         \

lib/ui/platform_dispatcher.dart

@@ -801,7 +801,7 @@ class PlatformDispatcher {
   ///
   ///  * [SchedulerBinding], the Flutter framework class which manages the
   ///    scheduling of frames.
-  ///  * [requestWarmUpFrame], a similar method that is used in rare cases that
+  ///  * [scheduleWarmUpFrame], a similar method that is used in rare cases that
   ///    a frame must be rendered immediately.
   void scheduleFrame() => _scheduleFrame();
 
@@ -816,7 +816,7 @@ class PlatformDispatcher {
   /// completed synchronously within this call.
   ///
   /// Prefer [scheduleFrame] to update the display in normal operation. The
-  /// [requestWarmUpFrame] method is designed for situations that require a frame is
+  /// [scheduleWarmUpFrame] method is designed for situations that require a frame is
   /// rendered as soon as possible, even at the cost of rendering quality. An
   /// example of using this method is [SchedulerBinding.scheduleWarmUpFrame],
   /// which is called during application startup so that the first frame can be
@@ -826,10 +826,16 @@ class PlatformDispatcher {
   ///
   ///  * [SchedulerBinding.scheduleWarmUpFrame], which uses this method.
   ///  * [scheduleFrame].
-  void requestWarmUpFrame() => _requestWarmUpFrame();
+  void scheduleWarmUpFrame(VoidCallback beginFrameCallback, VoidCallback drawFrameCallback) {
+    Timer.run(beginFrameCallback);
+    Timer.run(() {
+      drawFrameCallback();
+      _endWarmUpFrame();
+    });
+  }
 
-  @Native<Void Function()>(symbol: 'PlatformConfigurationNativeApi::RequestWarmUpFrame')
-  external static void _requestWarmUpFrame();
+  @Native<Void Function()>(symbol: 'PlatformConfigurationNativeApi::EndWarmUpFrame')
+  external static void _endWarmUpFrame();
 
   /// Additional accessibility features that may be enabled by the platform.
   AccessibilityFeatures get accessibilityFeatures => _configuration.accessibilityFeatures;

lib/ui/window/platform_configuration.cc

@@ -589,12 +589,9 @@ void PlatformConfigurationNativeApi::ScheduleFrame() {
   UIDartState::Current()->platform_configuration()->client()->ScheduleFrame();
 }
 
-void PlatformConfigurationNativeApi::RequestWarmUpFrame() {
+void PlatformConfigurationNativeApi::EndWarmUpFrame() {
   UIDartState::ThrowIfUIOperationsProhibited();
-  UIDartState::Current()
-      ->platform_configuration()
-      ->client()
-      ->RequestWarmUpFrame();
+  UIDartState::Current()->platform_configuration()->client()->EndWarmUpFrame();
 }
 
 void PlatformConfigurationNativeApi::UpdateSemantics(SemanticsUpdate* update) {

lib/ui/window/platform_configuration.h

@@ -68,7 +68,7 @@ class PlatformConfigurationClient {
   //--------------------------------------------------------------------------
   /// @brief
   ///
-  virtual void RequestWarmUpFrame() = 0;
+  virtual void EndWarmUpFrame() = 0;
 
   //--------------------------------------------------------------------------
   /// @brief      Updates the client's rendering on the GPU with the newly
@@ -562,7 +562,7 @@ class PlatformConfigurationNativeApi {
 
   static void ScheduleFrame();
 
-  static void RequestWarmUpFrame();
+  static void EndWarmUpFrame();
 
   static void Render(int64_t view_id,
                      Scene* scene,

lib/web_ui/lib/platform_dispatcher.dart

@@ -90,7 +90,7 @@ abstract class PlatformDispatcher {
 
   void scheduleFrame();
 
-  void requestWarmUpFrame();
+  void scheduleWarmUpFrame(VoidCallback beginFrameCallback, VoidCallback drawFrameCallback);
 
   Future<void> render(Scene scene, [FlutterView view]);
 

lib/web_ui/lib/src/engine/initialization.dart

@@ -102,30 +102,6 @@ void debugResetEngineInitializationState() {
   _initializationState = DebugEngineInitializationState.uninitialized;
 }
 
-void renderFrame(int timeMicroseconds) {
-  frameTimingsOnVsync();
-
-  // In Flutter terminology "building a frame" consists of "beginning
-  // frame" and "drawing frame".
-  //
-  // We do not call `frameTimingsOnBuildFinish` from here because
-  // part of the rasterization process, particularly in the HTML
-  // renderer, takes place in the `SceneBuilder.build()`.
-  frameTimingsOnBuildStart();
-  if (EnginePlatformDispatcher.instance.onBeginFrame != null) {
-    EnginePlatformDispatcher.instance.invokeOnBeginFrame(
-        Duration(microseconds: timeMicroseconds));
-  }
-
-  if (EnginePlatformDispatcher.instance.onDrawFrame != null) {
-    // TODO(yjbanov): technically Flutter flushes microtasks between
-    //                onBeginFrame and onDrawFrame. We don't, which hasn't
-    //                been an issue yet, but eventually we'll have to
-    //                implement it properly.
-    EnginePlatformDispatcher.instance.invokeOnDrawFrame();
-  }
-}
-
 /// Initializes non-UI engine services.
 ///
 /// Does not put any UI onto the page. It is therefore safe to call this
@@ -182,6 +158,8 @@ Future<void> initializeEngineServices({
     if (!waitingForAnimation) {
       waitingForAnimation = true;
       domWindow.requestAnimationFrame((JSNumber highResTime) {
+        frameTimingsOnVsync();
+
         // Reset immediately, because `frameHandler` can schedule more frames.
         waitingForAnimation = false;
 
@@ -192,13 +170,33 @@ Future<void> initializeEngineServices({
         // microsecond precision, and only then convert to `int`.
         final int highResTimeMicroseconds =
             (1000 * highResTime.toDartDouble).toInt();
-        renderFrame(highResTimeMicroseconds);
+
+        // In Flutter terminology "building a frame" consists of "beginning
+        // frame" and "drawing frame".
+        //
+        // We do not call `frameTimingsOnBuildFinish` from here because
+        // part of the rasterization process, particularly in the HTML
+        // renderer, takes place in the `SceneBuilder.build()`.
+        frameTimingsOnBuildStart();
+        if (EnginePlatformDispatcher.instance.onBeginFrame != null) {
+          EnginePlatformDispatcher.instance.invokeOnBeginFrame(
+              Duration(microseconds: highResTimeMicroseconds));
+        }
+
+        if (EnginePlatformDispatcher.instance.onDrawFrame != null) {
+          // TODO(yjbanov): technically Flutter flushes microtasks between
+          //                onBeginFrame and onDrawFrame. We don't, which hasn't
+          //                been an issue yet, but eventually we'll have to
+          //                implement it properly.
+          EnginePlatformDispatcher.instance.invokeOnDrawFrame();
+        }
       });
     }
   };
-  requestWarmUpFrameCallback = () {
-    final int timeMicroseconds = (1000 * domWindow.performance.now()).toInt();
-    renderFrame(timeMicroseconds);
+
+  scheduleWarmUpFrameCallback = (ui.VoidCallback beginFrameCallback, ui.VoidCallback drawFrameCallback) {
+    Timer.run(beginFrameCallback);
+    Timer.run(drawFrameCallback);
   };
 
   assetManager ??= ui_web.AssetManager(assetBase: configuration.assetBase);

lib/web_ui/lib/src/engine/platform_dispatcher.dart

@@ -17,12 +17,16 @@ import '../engine.dart';
 /// This may be overridden in tests, for example, to pump fake frames.
 ui.VoidCallback? scheduleFrameCallback;
 
+/// Signature of the function to schedule a warm up frame with the specified
+/// frame callbacks.
+typedef ScheduleWarmUpFrameCallback = void Function(ui.VoidCallback beginFrameCallback, ui.VoidCallback drawFrameCallback);
+
 /// Requests that the framework tries to render a frame immediately.
 ///
 /// Since this will probably call [PlatformWindow.render] outside of an
 /// animation frame, the render will not be actually presented, but just to warm
 /// up the framework.
-ui.VoidCallback? requestWarmUpFrameCallback;
+ScheduleWarmUpFrameCallback? scheduleWarmUpFrameCallback;
 
 /// Signature of functions added as a listener to high contrast changes
 typedef HighContrastListener = void Function(bool enabled);
@@ -779,11 +783,11 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   }
 
   @override
-  void requestWarmUpFrame() {
-    if (requestWarmUpFrameCallback == null) {
-      throw Exception('requestWarmUpFrameCallback must be initialized first.');
+  void scheduleWarmUpFrame(ui.VoidCallback beginFrameCallback, ui.VoidCallback drawFrameCallback) {
+    if (scheduleWarmUpFrameCallback == null) {
+      throw Exception('scheduleWarmUpFrameCallback must be initialized first.');
     }
-    requestWarmUpFrameCallback!();
+    scheduleWarmUpFrameCallback!(beginFrameCallback, drawFrameCallback);
   }
 
   /// Updates the application's rendering on the GPU with the newly provided

runtime/runtime_controller.cc

@@ -341,8 +341,8 @@ void RuntimeController::ScheduleFrame() {
 }
 
 // |PlatformConfigurationClient|
-void RuntimeController::RequestWarmUpFrame() {
-  client_.RequestWarmUpFrame();
+void RuntimeController::EndWarmUpFrame() {
+  client_.EndWarmUpFrame();
 }
 
 // |PlatformConfigurationClient|

runtime/runtime_controller.h

@@ -658,7 +658,7 @@ class RuntimeController : public PlatformConfigurationClient {
   void ScheduleFrame() override;
 
   // |PlatformConfigurationClient|
-  void RequestWarmUpFrame() override;
+  void EndWarmUpFrame() override;
 
   // |PlatformConfigurationClient|
   void Render(Scene* scene, double width, double height) override;

runtime/runtime_delegate.h

@@ -25,7 +25,7 @@ class RuntimeDelegate {
 
   virtual void ScheduleFrame(bool regenerate_layer_trees = true) = 0;
 
-  virtual void RequestWarmUpFrame() = 0;
+  virtual void EndWarmUpFrame() = 0;
 
   virtual void Render(std::unique_ptr<flutter::LayerTree> layer_tree,
                       float device_pixel_ratio) = 0;

shell/common/animator.cc

@@ -264,18 +264,10 @@ void Animator::AwaitVSync() {
   }
 }
 
-void Animator::RequestWarmUpFrame() {
-  TRACE_EVENT_ASYNC_BEGIN0("flutter", "Forced Frame Request Pending",
-                           frame_request_number_);
-  regenerate_layer_trees_ = true;
-
-  const fml::TimePoint frame_start_time = fml::TimePoint::Now();
-  const fml::TimePoint frame_target_time = frame_start_time;
-
-  std::unique_ptr<FrameTimingsRecorder> frame_timings_recorder =
-      std::make_unique<FrameTimingsRecorder>();
-  frame_timings_recorder->RecordVsync(frame_start_time, frame_target_time);
-  BeginFrame(std::move(frame_timings_recorder));
+void Animator::EndWarmUpFrame() {
+  // Do nothing. The warm up frame does not need any additional work to end the
+  // frame for now. This will change once the pipeline supports multi-view.
+  // https://github.com/flutter/flutter/issues/142851
 }
 
 void Animator::ScheduleSecondaryVsyncCallback(uintptr_t id,

shell/common/animator.h

@@ -53,7 +53,7 @@ class Animator final {
 
   void RequestFrame(bool regenerate_layer_trees = true);
 
-  void RequestWarmUpFrame();
+  void EndWarmUpFrame();
 
   //--------------------------------------------------------------------------
   /// @brief    Tells the Animator that this frame needs to render another view.

shell/common/engine.cc

@@ -462,8 +462,8 @@ void Engine::ScheduleFrame(bool regenerate_layer_trees) {
   animator_->RequestFrame(regenerate_layer_trees);
 }
 
-void Engine::RequestWarmUpFrame() {
-  animator_->RequestWarmUpFrame();
+void Engine::EndWarmUpFrame() {
+  animator_->EndWarmUpFrame();
 }
 
 void Engine::Render(std::unique_ptr<flutter::LayerTree> layer_tree,

shell/common/engine.h

@@ -838,7 +838,7 @@ class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
   void ScheduleFrame() { ScheduleFrame(true); }
 
   // |RuntimeDelegate|
-  void RequestWarmUpFrame() override;
+  void EndWarmUpFrame() override;
 
   // |RuntimeDelegate|
   FontCollection& GetFontCollection() override;

shell/common/engine_unittests.cc

@@ -63,7 +63,7 @@ class MockRuntimeDelegate : public RuntimeDelegate {
  public:
   MOCK_METHOD(std::string, DefaultRouteName, (), (override));
   MOCK_METHOD(void, ScheduleFrame, (bool), (override));
-  MOCK_METHOD(void, RequestWarmUpFrame, (), (override));
+  MOCK_METHOD(void, EndWarmUpFrame, (), (override));
   MOCK_METHOD(void,
               Render,
               (std::unique_ptr<flutter::LayerTree>, float),