[iOS] Fix jitter keyboard animation by updating metrics value in onFrameRasterized callback.

shell/common/shell.cc

@@ -1510,6 +1510,25 @@ void Shell::OnFrameRasterized(const FrameTiming& timing) {
         },
         fml::TimeDelta::FromMilliseconds(kBatchTimeInMilliseconds));
   }
+
+  {
+    FML_LOG(ERROR) << "FireOnFrameRasteized";
+    std::scoped_lock lock(on_frame_rasterized_listener_mutex_);
+    for (auto pair : on_frame_rasterized_map_) {
+      auto value_pair = pair.second;
+      fml::closure callback = value_pair.second;
+      fml::AutoResetWaitableEvent latch;
+      fml::TaskRunner::RunNowOrPostTask(value_pair.first, [callback, &latch] {
+        callback();
+        FML_LOG(ERROR) << "Single1";
+        latch.Signal();
+        FML_LOG(ERROR) << "Single2";
+      });
+      FML_LOG(ERROR) << "Wait1";
+      latch.Wait();
+      FML_LOG(ERROR) << "Wait2";
+    }
+  }
 }
 
 fml::Milliseconds Shell::GetFrameBudget() {
@@ -1749,6 +1768,21 @@ void Shell::RegisterImageDecoder(ImageGeneratorFactory factory,
       });
 }
 
+void Shell::RegisterOnFrameRasterizedCallback(
+    const std::string_view& key,
+    const fml::closure& callback,
+    const fml::RefPtr<fml::TaskRunner>& taskRunner) {
+  FML_LOG(ERROR) << "RegisterOnFrameRasterizedCallback";
+  std::scoped_lock lock(on_frame_rasterized_listener_mutex_);
+  on_frame_rasterized_map_[key] = {taskRunner, callback};
+}
+
+void Shell::UnregisterOnFrameRasterizedCallback(const std::string_view& key) {
+  FML_LOG(ERROR) << "UnregisterOnFrameRasterizedCallback";
+  std::scoped_lock lock(on_frame_rasterized_listener_mutex_);
+  on_frame_rasterized_map_.erase(key);
+}
+
 bool Shell::OnServiceProtocolGetSkSLs(
     const ServiceProtocol::Handler::ServiceProtocolMap& params,
     rapidjson::Document* response) {

shell/common/shell.h

@@ -397,6 +397,15 @@ class Shell final : public PlatformView::Delegate,
   /// @see        `CreateCompatibleGenerator`
   void RegisterImageDecoder(ImageGeneratorFactory factory, int32_t priority);
 
+  /// TODO: Add comments.
+  void RegisterOnFrameRasterizedCallback(
+      const std::string_view& key,
+      const fml::closure& callback,
+      const fml::RefPtr<fml::TaskRunner>& taskRunner);
+
+  /// TODO: Add comments
+  void UnregisterOnFrameRasterizedCallback(const std::string_view& key);
+
   // |Engine::Delegate|
   const std::shared_ptr<PlatformMessageHandler>& GetPlatformMessageHandler()
       const override;
@@ -474,6 +483,15 @@ class Shell final : public PlatformView::Delegate,
   // Used to communicate the right frame bounds via service protocol.
   double device_pixel_ratio_ = 0.0;
 
+  // Manage the listeners that get notified when |OnFrameRasterized|
+  std::mutex on_frame_rasterized_listener_mutex_;
+  std::unordered_map<std::string_view,  // listener key
+                     std::pair<fml::RefPtr<fml::TaskRunner>,
+                               fml::closure>  // task-runner/function
+                                              // pair
+                     >
+      on_frame_rasterized_map_;
+
   // How many frames have been timed since last report.
   size_t UnreportedFramesCount() const;
 

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -1587,9 +1587,9 @@ - (void)setupKeyboardSpringAnimationIfNeeded:(CAAnimation*)keyboardAnimation {
                 toValue:self.targetViewInsetBottom]);
 }
 
+/// TODO rename to `registerOnFrameRasterizedCallback`
 - (void)setupKeyboardAnimationVsyncClient {
-  auto callback = [weakSelf =
-                       [self getWeakPtr]](std::unique_ptr<flutter::FrameTimingsRecorder> recorder) {
+  auto onFrameRasterizedCallback = [weakSelf = [self getWeakPtr]] {
     if (!weakSelf) {
       return;
     }
@@ -1600,7 +1600,8 @@ - (void)setupKeyboardAnimationVsyncClient {
     }
 
     if ([flutterViewController keyboardAnimationView].superview == nil) {
-      // Ensure the keyboardAnimationView is in view hierarchy when animation running.
+      // Ensure the keyboardAnimationView is in view hierarchy when
+      // animation running.
       [flutterViewController.get().view addSubview:[flutterViewController keyboardAnimationView]];
     }
 
@@ -1612,28 +1613,22 @@ - (void)setupKeyboardAnimationVsyncClient {
         [flutterViewController updateViewportMetrics];
       }
     } else {
-      fml::TimeDelta timeElapsed = recorder.get()->GetVsyncTargetTime() -
-                                   flutterViewController.get().keyboardAnimationStartTime;
-
+      fml::TimeDelta timeElapsed =
+          fml::TimePoint::Now() - flutterViewController.get().keyboardAnimationStartTime;
       flutterViewController.get()->_viewportMetrics.physical_view_inset_bottom =
           [[flutterViewController keyboardSpringAnimation] curveFunction:timeElapsed.ToSecondsF()];
       [flutterViewController updateViewportMetrics];
-    }
+    };
   };
   flutter::Shell& shell = [_engine.get() shell];
-  NSAssert(_keyboardAnimationVSyncClient == nil,
-           @"_keyboardAnimationVSyncClient must be nil when setup");
-  _keyboardAnimationVSyncClient =
-      [[VSyncClient alloc] initWithTaskRunner:shell.GetTaskRunners().GetPlatformTaskRunner()
-                                     callback:callback];
-  _keyboardAnimationVSyncClient.allowPauseAfterVsync = NO;
-  [_keyboardAnimationVSyncClient await];
+  shell.RegisterOnFrameRasterizedCallback("flutterVCKeyboard", onFrameRasterizedCallback,
+                                          shell.GetTaskRunners().GetPlatformTaskRunner());
 }
 
+/// TODO rename to `unregisterOnFrameRasterizedCallback`
 - (void)invalidateKeyboardAnimationVSyncClient {
-  [_keyboardAnimationVSyncClient invalidate];
-  [_keyboardAnimationVSyncClient release];
-  _keyboardAnimationVSyncClient = nil;
+  flutter::Shell& shell = [_engine.get() shell];
+  shell.UnregisterOnFrameRasterizedCallback("flutterVCKeyboard");
 }
 
 - (void)removeKeyboardAnimationView {