Extract Win32 runtime state storage

src/platform_windows/windows_runtime_shell.cpp

@@ -8,6 +8,7 @@
 #include "platform_windows/windows_lifecycle_state.h"
 #include "platform_windows/windows_main_window_session.h"
 #include "platform_windows/windows_platform_services.h"
+#include "platform_windows/windows_runtime_state.h"
 #include "platform_windows/windows_stylus_input.h"
 #include "platform_windows/windows_window_shell.h"
 #include "wacom.h"
@@ -17,17 +18,6 @@ namespace pp::platform::windows {
 
 namespace {
 
-struct RetainedWindowsRuntimeState final {
-    std::unique_ptr<App> owned_app;
-    WacomTablet tablet;
-};
-
-[[nodiscard]] RetainedWindowsRuntimeState& retained_runtime_state()
-{
-    static RetainedWindowsRuntimeState state;
-    return state;
-}
-
 void register_touch_window(HWND hWnd)
 {
     // link: https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-registertouchwindow
@@ -110,7 +100,7 @@ void run_main_message_loop()
 
 void shutdown_main_window_runtime(const MainWindowStartupState& startup, HINSTANCE hInst)
 {
-    retained_runtime_state().tablet.terminate();
+    retained_wacom_tablet().terminate();
     UnregisterClass(startup.window_class.lpszClassName, hInst);
     LogRemote::I.stop();
 }
@@ -130,21 +120,21 @@ App* bound_app() noexcept
 void release_bound_app() noexcept
 {
     bind_app(nullptr);
-    retained_runtime_state().owned_app.reset();
+    retained_owned_app().reset();
 }
 
 WacomTablet* bound_wacom_tablet() noexcept
 {
-    return &retained_runtime_state().tablet;
+    return &retained_wacom_tablet();
 }
 
 int run_main_application(int argc, char** argv)
 {
     const auto instance = GetModuleHandle(NULL);
 
-    auto& runtime_state = retained_runtime_state();
-    runtime_state.owned_app = std::make_unique<App>();
-    auto* app = runtime_state.owned_app.get();
+    auto& owned_app = retained_owned_app();
+    owned_app = std::make_unique<App>();
+    auto* app = owned_app.get();
     bind_app(app);
     app->set_platform_services(&pp::platform::windows::platform_services());
     app->initLog();