Refactor desktop window management and tray

windows/runner/flutter_window.cpp

@@ -28,7 +28,8 @@ bool FlutterWindow::OnCreate() {
   SetChildContent(flutter_controller_->view()->GetNativeWindow());
 
   flutter_controller_->engine()->SetNextFrameCallback([&]() {
-    this->Show();
+    // this->Show(); window_manager hidden at launch
+    ""
   });
 
   // Flutter can complete the first frame before the "show window" callback is

windows/runner/win32_window.cpp

@@ -135,7 +135,9 @@ bool Win32Window::Create(const std::wstring& title,
   double scale_factor = dpi / 96.0;
 
   HWND window = CreateWindow(
-      window_class, title.c_str(), WS_OVERLAPPEDWINDOW,
+      // window_class, title.c_str(), WS_OVERLAPPEDWINDOW, // window_manager hidden at launch
+      window_class, title.c_str(),
+      WS_OVERLAPPEDWINDOW, // do not add WS_VISIBLE since the window will be shown later
       Scale(origin.x, scale_factor), Scale(origin.y, scale_factor),
       Scale(size.width, scale_factor), Scale(size.height, scale_factor),
       nullptr, nullptr, GetModuleHandle(nullptr), this);