fix buffer lock

windows/webview_cef_plugin.cpp

@@ -26,12 +26,12 @@ namespace webview_cef {
  std::unique_ptr<uint8_t> backing_pixel_buffer;
  std::mutex buffer_mutex_;
  std::unique_ptr<flutter::TextureVariant> m_texture = std::make_unique<flutter::TextureVariant>(flutter::PixelBufferTexture([](size_t width, size_t height) -> const FlutterDesktopPixelBuffer* {
+ buffer_mutex_.lock();
  auto buffer = pixel_buffer.get();
  // Only lock the mutex if the buffer is not null
  // (to ensure the release callback gets called)
- if (buffer) {
- // Gets unlocked in the FlutterDesktopPixelBuffer's release callback.
- buffer_mutex_.lock();
+ if (!buffer) {
+ buffer_mutex_.unlock();
  }
  return buffer;
  }));