Reland "Smooth out iOS irregular input events delivery (#12280)"

ci/licenses_golden/licenses_flutter

@@ -486,6 +486,7 @@ FILE: ../../../flutter/shell/common/canvas_spy_unittests.cc
 FILE: ../../../flutter/shell/common/engine.cc
 FILE: ../../../flutter/shell/common/engine.h
 FILE: ../../../flutter/shell/common/fixtures/shell_test.dart
+FILE: ../../../flutter/shell/common/input_events_unittests.cc
 FILE: ../../../flutter/shell/common/isolate_configuration.cc
 FILE: ../../../flutter/shell/common/isolate_configuration.h
 FILE: ../../../flutter/shell/common/persistent_cache.cc
@@ -495,6 +496,8 @@ FILE: ../../../flutter/shell/common/pipeline.h
 FILE: ../../../flutter/shell/common/pipeline_unittests.cc
 FILE: ../../../flutter/shell/common/platform_view.cc
 FILE: ../../../flutter/shell/common/platform_view.h
+FILE: ../../../flutter/shell/common/pointer_data_dispatcher.cc
+FILE: ../../../flutter/shell/common/pointer_data_dispatcher.h
 FILE: ../../../flutter/shell/common/rasterizer.cc
 FILE: ../../../flutter/shell/common/rasterizer.h
 FILE: ../../../flutter/shell/common/run_configuration.cc

shell/common/BUILD.gn

@@ -74,6 +74,8 @@ source_set("common") {
     "pipeline.h",
     "platform_view.cc",
     "platform_view.h",
+    "pointer_data_dispatcher.cc",
+    "pointer_data_dispatcher.h",
     "rasterizer.cc",
     "rasterizer.h",
     "run_configuration.cc",
@@ -156,6 +158,7 @@ if (current_toolchain == host_toolchain) {
   shell_host_executable("shell_unittests") {
     sources = [
       "canvas_spy_unittests.cc",
+      "input_events_unittests.cc",
       "pipeline_unittests.cc",
       "shell_test.cc",
       "shell_test.h",

shell/common/animator.cc

@@ -244,4 +244,8 @@ void Animator::AwaitVSync() {
   delegate_.OnAnimatorNotifyIdle(dart_frame_deadline_);
 }
 
+void Animator::ScheduleSecondaryVsyncCallback(fml::closure callback) {
+  waiter_->ScheduleSecondaryCallback(std::move(callback));
+}
+
 }  // namespace flutter

shell/common/animator.h

@@ -52,6 +52,23 @@ class Animator final {
 
   void Render(std::unique_ptr<flutter::LayerTree> layer_tree);
 
+  //--------------------------------------------------------------------------
+  /// @brief    Schedule a secondary callback to be executed right after the
+  ///           main `VsyncWaiter::AsyncWaitForVsync` callback (which is added
+  ///           by `Animator::RequestFrame`).
+  ///
+  ///           Like the callback in `AsyncWaitForVsync`, this callback is
+  ///           only scheduled to be called once, and it's supposed to be
+  ///           called in the UI thread. If there is no AsyncWaitForVsync
+  ///           callback (`Animator::RequestFrame` is not called), this
+  ///           secondary callback will still be executed at vsync.
+  ///
+  ///           This callback is used to provide the vsync signal needed by
+  ///           `SmoothPointerDataDispatcher`.
+  ///
+  /// @see      `PointerDataDispatcher::ScheduleSecondaryVsyncCallback`.
+  void ScheduleSecondaryVsyncCallback(fml::closure callback);
+
   void Start();
 
   void Stop();

shell/common/engine.cc

@@ -36,6 +36,7 @@ static constexpr char kSettingsChannel[] = "flutter/settings";
 static constexpr char kIsolateChannel[] = "flutter/isolate";
 
 Engine::Engine(Delegate& delegate,
+               const PointerDataDispatcherMaker& dispatcher_maker,
                DartVM& vm,
                fml::RefPtr<const DartSnapshot> isolate_snapshot,
                fml::RefPtr<const DartSnapshot> shared_snapshot,
@@ -51,6 +52,7 @@ Engine::Engine(Delegate& delegate,
       image_decoder_(task_runners,
                      vm.GetConcurrentWorkerTaskRunner(),
                      io_manager),
+      task_runners_(std::move(task_runners)),
       weak_factory_(this) {
   // Runtime controller is initialized here because it takes a reference to this
   // object as its delegate. The delegate may be called in the constructor and
@@ -60,7 +62,7 @@ Engine::Engine(Delegate& delegate,
       &vm,                                   // VM
       std::move(isolate_snapshot),           // isolate snapshot
       std::move(shared_snapshot),            // shared snapshot
-      std::move(task_runners),               // task runners
+      task_runners_,                         // task runners
       std::move(io_manager),                 // io manager
       image_decoder_.GetWeakPtr(),           // image decoder
       settings_.advisory_script_uri,         // advisory script uri
@@ -69,6 +71,8 @@ Engine::Engine(Delegate& delegate,
       settings_.isolate_create_callback,     // isolate create callback
       settings_.isolate_shutdown_callback    // isolate shutdown callback
   );
+
+  pointer_data_dispatcher_ = dispatcher_maker(*this);
 }
 
 Engine::~Engine() = default;
@@ -381,12 +385,12 @@ void Engine::HandleSettingsPlatformMessage(PlatformMessage* message) {
   }
 }
 
-void Engine::DispatchPointerDataPacket(const PointerDataPacket& packet,
-                                       uint64_t trace_flow_id) {
+void Engine::DispatchPointerDataPacket(
+    std::unique_ptr<PointerDataPacket> packet,
+    uint64_t trace_flow_id) {
   TRACE_EVENT0("flutter", "Engine::DispatchPointerDataPacket");
   TRACE_FLOW_STEP("flutter", "PointerEvent", trace_flow_id);
-  animator_->EnqueueTraceFlowId(trace_flow_id);
-  runtime_controller_->DispatchPointerDataPacket(packet);
+  pointer_data_dispatcher_->DispatchPacket(std::move(packet), trace_flow_id);
 }
 
 void Engine::DispatchSemanticsAction(int id,
@@ -462,6 +466,18 @@ FontCollection& Engine::GetFontCollection() {
   return font_collection_;
 }
 
+void Engine::DoDispatchPacket(std::unique_ptr<PointerDataPacket> packet,
+                              uint64_t trace_flow_id) {
+  animator_->EnqueueTraceFlowId(trace_flow_id);
+  if (runtime_controller_) {
+    runtime_controller_->DispatchPointerDataPacket(*packet);
+  }
+}
+
+void Engine::ScheduleSecondaryVsyncCallback(fml::closure callback) {
+  animator_->ScheduleSecondaryVsyncCallback(std::move(callback));
+}
+
 void Engine::HandleAssetPlatformMessage(fml::RefPtr<PlatformMessage> message) {
   fml::RefPtr<PlatformMessageResponse> response = message->response();
   if (!response) {

shell/common/engine.h

@@ -22,6 +22,8 @@
 #include "flutter/runtime/runtime_controller.h"
 #include "flutter/runtime/runtime_delegate.h"
 #include "flutter/shell/common/animator.h"
+#include "flutter/shell/common/platform_view.h"
+#include "flutter/shell/common/pointer_data_dispatcher.h"
 #include "flutter/shell/common/rasterizer.h"
 #include "flutter/shell/common/run_configuration.h"
 #include "flutter/shell/common/shell_io_manager.h"
@@ -65,7 +67,7 @@ namespace flutter {
 ///           name and it does happen to be one of the older classes in the
 ///           repository.
 ///
-class Engine final : public RuntimeDelegate {
+class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
  public:
   //----------------------------------------------------------------------------
   /// @brief      Indicates the result of the call to `Engine::Run`.
@@ -234,6 +236,12 @@ class Engine final : public RuntimeDelegate {
   ///                                tasks that require access to components
   ///                                that cannot be safely accessed by the
   ///                                engine. This is the shell.
+  /// @param      dispatcher_maker   The callback provided by `PlatformView` for
+  ///                                engine to create the pointer data
+  ///                                dispatcher. Similar to other engine
+  ///                                resources, this dispatcher_maker and its
+  ///                                returned dispatcher is only safe to be
+  ///                                called from the UI thread.
   /// @param      vm                 An instance of the running Dart VM.
   /// @param[in]  isolate_snapshot   The snapshot used to create the root
   ///                                isolate. Even though the isolate is not
@@ -265,6 +273,7 @@ class Engine final : public RuntimeDelegate {
   ///                                GPU.
   ///
   Engine(Delegate& delegate,
+         const PointerDataDispatcherMaker& dispatcher_maker,
          DartVM& vm,
          fml::RefPtr<const DartSnapshot> isolate_snapshot,
          fml::RefPtr<const DartSnapshot> shared_snapshot,
@@ -649,7 +658,7 @@ class Engine final : public RuntimeDelegate {
   ///                            timeline and allow grouping frames and input
   ///                            events into logical chunks.
   ///
-  void DispatchPointerDataPacket(const PointerDataPacket& packet,
+  void DispatchPointerDataPacket(std::unique_ptr<PointerDataPacket> packet,
                                  uint64_t trace_flow_id);
 
   //----------------------------------------------------------------------------
@@ -700,18 +709,32 @@ class Engine final : public RuntimeDelegate {
   // |RuntimeDelegate|
   FontCollection& GetFontCollection() override;
 
+  // |PointerDataDispatcher::Delegate|
+  void DoDispatchPacket(std::unique_ptr<PointerDataPacket> packet,
+                        uint64_t trace_flow_id) override;
+
+  // |PointerDataDispatcher::Delegate|
+  void ScheduleSecondaryVsyncCallback(fml::closure callback) override;
+
  private:
   Engine::Delegate& delegate_;
   const Settings settings_;
   std::unique_ptr<Animator> animator_;
   std::unique_ptr<RuntimeController> runtime_controller_;
+
+  // The pointer_data_dispatcher_ depends on animator_ and runtime_controller_.
+  // So it should be defined after them to ensure that pointer_data_dispatcher_
+  // is destructed first.
+  std::unique_ptr<PointerDataDispatcher> pointer_data_dispatcher_;
+
   std::string initial_route_;
   ViewportMetrics viewport_metrics_;
   std::shared_ptr<AssetManager> asset_manager_;
   bool activity_running_;
   bool have_surface_;
   FontCollection font_collection_;
   ImageDecoder image_decoder_;
+  TaskRunners task_runners_;
   fml::WeakPtrFactory<Engine> weak_factory_;
 
   // |RuntimeDelegate|

shell/common/fixtures/shell_test.dart

@@ -11,6 +11,7 @@ void main() {}
 
 void nativeReportTimingsCallback(List<int> timings) native 'NativeReportTimingsCallback';
 void nativeOnBeginFrame(int microseconds) native 'NativeOnBeginFrame';
+void nativeOnPointerDataPacket() native 'NativeOnPointerDataPacket';
 
 @pragma('vm:entry-point')
 void reportTimingsMain() {
@@ -32,6 +33,13 @@ void onBeginFrameMain() {
   };
 }
 
+@pragma('vm:entry-point')
+void onPointerDataPacketMain() {
+  window.onPointerDataPacket = (PointerDataPacket packet) {
+    nativeOnPointerDataPacket();
+  };
+}
+
 @pragma('vm:entry-point')
 void emptyMain() {}