make managed deferredrenderer lock global.

src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs

@@ -339,7 +339,7 @@ namespace Avalonia.Win32
 
                 case WindowsMessage.WM_PAINT:
                     {
-                        using (_rendererLock.Lock())
+                        using (s_rendererLock.Lock())
                         {
                             if (BeginPaint(_hwnd, out PAINTSTRUCT ps) != IntPtr.Zero)
                             {
@@ -356,7 +356,7 @@ namespace Avalonia.Win32
 
                 case WindowsMessage.WM_SIZE:
                     {
-                        using (_rendererLock.Lock())
+                        using (s_rendererLock.Lock())
                         {
                             // Do nothing here, just block until the pending frame render is completed on the render thread
                         }
@@ -464,7 +464,7 @@ namespace Avalonia.Win32
                 }
             }
 
-            using (_rendererLock.Lock())
+            using (s_rendererLock.Lock())
             {
                 return DefWindowProc(hWnd, msg, wParam, lParam);
             }

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -56,7 +56,7 @@ namespace Avalonia.Win32
         private const WindowStyles WindowStateMask = (WindowStyles.WS_MAXIMIZE | WindowStyles.WS_MINIMIZE);
         private readonly TouchDevice _touchDevice;
         private readonly MouseDevice _mouseDevice;
-        private readonly ManagedDeferredRendererLock _rendererLock;
+        private static readonly ManagedDeferredRendererLock s_rendererLock = new ManagedDeferredRendererLock();
         private readonly FramebufferManager _framebuffer;
         private readonly IGlPlatformSurface _gl;
 
@@ -100,7 +100,6 @@ namespace Avalonia.Win32
                 IsResizable = true,
                 Decorations = SystemDecorations.Full
             };
-            _rendererLock = new ManagedDeferredRendererLock();
 
             _isUsingComposition = Win32Platform.Options.UseWindowsUIComposition &&
                 Win32Platform.WindowsVersion.Major >= 10 && Win32Platform.WindowsVersion.Build >= 16299 &&
@@ -443,7 +442,7 @@ namespace Avalonia.Win32
                 return customRendererFactory.Create(root, loop);
 
             return Win32Platform.UseDeferredRendering ?
-                (IRenderer)new DeferredRenderer(root, loop, rendererLock: _rendererLock) :
+                (IRenderer)new DeferredRenderer(root, loop, rendererLock: s_rendererLock) :
                 new ImmediateRenderer(root);
         }