minor bug fixes

Samples/UIWidgetsSamples_2019_4/Assets/Editor/EditorWindowSample/UIWidgetsEditorWindowSample.asmdef

     "name": "UIWidgetsEditorWindowSample",
     "references": [
         "Unity.UIWidgets",
-        "Unity.UIWidgets.Editor"
+        "Unity.UIWidgets.Editor",
+        "UIWidgetsGallery"
     ],
     "optionalUnityReferences": [],
     "includePlatforms": [],

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/cupertino/cupertino_switch_demo.cs

 using Unity.UIWidgets.widgets;
 
 namespace UIWidgetsGallery.gallery {
-    class CupertinoSwitchDemo : StatefulWidget {
+    public class CupertinoSwitchDemo : StatefulWidget {
         public static string routeName = "/cupertino/switch";
 
         public override State createState() => new _CupertinoSwitchDemoState();

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsSample.asmdef

 {
     "name": "UIWidgetsSample",
     "references": [
-        "Unity.UIWidgets"
+        "Unity.UIWidgets",
+        "UIWidgetsGallery"
     ],
     "optionalUnityReferences": [],
     "includePlatforms": [],

com.unity.uiwidgets/Editor/UIWidgetsEditorPanel.cs

 using System.Collections;
 using System.Collections.Generic;
-using uiwidgets;
-using Unity.UIWidgets.widgets;
 using UnityEditor;
 using UnityEngine;
 using Rect = UnityEngine.Rect;
                 }
                 
                 GUI.DrawTexture(new Rect(0.0f, 0.0f, position.width, position.height), _wrapper.renderTexture);
-
                 Input_OnGUIEvent(Event.current);
             }
         }

com.unity.uiwidgets/Runtime/engine2/UIWidgetsPanel.cs

         void Input_OnDisable() {
         }
 
-        public void Input_Update() {
+        void Input_Update() {
             if (Input.touchCount == 0 && Input.mousePresent) {
                 if (_isEntered) {
                     if (!Input.GetMouseButton(0) && !Input.GetMouseButton(1) && !Input.GetMouseButton(2)) {
             }
         }
 
-        public void Input_OnGUI() {
+        void Input_OnGUI() {
             Event e = Event.current;
             if (e.isKey) {
                 _wrapper.OnKeyDown(e);

engine/src/shell/platform/unity/windows/uiwidgets_system.cc

 
 void UIWidgetsSystem::GfxWorkerCallback(int eventId, void* data) {
   const fml::closure task(std::move(gfx_worker_tasks_[eventId]));
-  gfx_worker_tasks_.erase(eventId);
-
+  {
+    std::scoped_lock(task_mutex_);
+    gfx_worker_tasks_.erase(eventId);
+  }
-  last_task_id_++;
-  gfx_worker_tasks_[last_task_id_] = task;
+  {
+    std::scoped_lock(task_mutex_);
+    last_task_id_++;
+    gfx_worker_tasks_[last_task_id_] = task;
+  }
   unity_uiwidgets_->IssuePluginEventAndData(&_GfxWorkerCallback, last_task_id_,
                                             nullptr);
 }

engine/src/shell/platform/unity/windows/uiwidgets_system.h

 #include <cstdarg>
 #include <set>
 #include <unordered_map>
+#include <mutex>
 
 #include "Unity/IUnityInterface.h"
 #include "Unity/IUnityUIWidgets.h"
 
   TimePoint next_uiwidgets_event_time_ = TimePoint::clock::now();
   std::set<UIWidgetsPanel*> uiwidgets_panels_;
+
+  std::mutex task_mutex_;
 };
 
 }  // namespace uiwidgets

Samples/UIWidgetsSamples_2019_4/Assets/Editor/EditorWindowSample/GalleryMain.cs

+using UIWidgetsGallery.gallery;
+using Unity.UIWidgets.Editor;
+using UnityEditor;
+using ui_ = Unity.UIWidgets.widgets.ui_;
+
+namespace UIWidgetsEditorWindowSample
+{
+    public class EditorWindowGallery : UIWidgetsEditorPanel
+    {
+        [MenuItem("UIWidgets/EditorSample")]
+        public static void CountDemo()
+        {
+            CreateWindow<EditorWindowGallery>();
+        }
+        
+        protected override void main()
+        {
+            ui_.runApp(new GalleryApp());
+        }
+    }
+}

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/UIWidgetsGallery.asmdef

+{
+    "name": "UIWidgetsGallery",
+    "references": [
+        "Unity.UIWidgets"
+    ],
+    "optionalUnityReferences": [],
+    "includePlatforms": [],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [],
+    "autoReferenced": true,
+    "defineConstraints": []
+}

Samples/UIWidgetsSamples_2019_4/Assets/Editor/EditorWindowSample/CountDemo.cs

-using System.Collections.Generic;
-using Unity.UIWidgets.cupertino;
-using Unity.UIWidgets.Editor;
-using Unity.UIWidgets.ui;
-using Unity.UIWidgets.widgets;
-using UnityEditor;
-using Text = Unity.UIWidgets.widgets.Text;
-using ui_ = Unity.UIWidgets.widgets.ui_;
-using TextStyle = Unity.UIWidgets.painting.TextStyle;
-
-namespace UIWidgetsEditorWindowSample
-{
-    public class EditorWindowCountDemo : UIWidgetsEditorPanel
-    {
-        [MenuItem("UIWidgets/CountDemo")]
-        public static void CountDemo()
-        {
-            CreateWindow<EditorWindowCountDemo>();
-        }
-        
-        protected override void main()
-        {
-            ui_.runApp(new MyApp());
-        }
-
-        class MyApp : StatelessWidget
-        {
-            public override Widget build(BuildContext context)
-            {
-                return new CupertinoApp(
-                    home: new EditorWindowCounterApp()
-                );
-            }
-        }
-    }
-
-    internal class EditorWindowCounterApp : StatefulWidget
-    {
-        public override State createState()
-        {
-            return new EditorWindowCounterState();
-        }
-    }
-
-    internal class EditorWindowCounterState : State<EditorWindowCounterApp>
-    {
-        private int count = 0;
-
-        public override Widget build(BuildContext context)
-        {
-            return new Container(
-                color: Color.fromARGB(255, 255, 0, 0),
-                child: new Column(children: new List<Widget>()
-                    {
-                        new Text($"count: {count}", style: new TextStyle(color: Color.fromARGB(255, 0 ,0 ,255))),
-                        new CupertinoButton(
-                            onPressed: () =>
-                            {
-                                setState(() =>
-                                {
-                                    count++;
-                                });
-                            },
-                            child: new Container(
-                                color: Color.fromARGB(255,0 , 255, 0),
-                                width: 100,
-                                height: 40
-                            )
-                        ),
-                    }
-                )
-            );
-        }
-    }
-}