refactor Windows classes to separate EGL/WGL/Backing Window

windows/opengl_texture_buffer.h

@@ -16,25 +16,24 @@
 #include <Windows.h>
 #include <wrl.h>
 
+#include "flutter_texture_buffer.h"
+
 typedef uint32_t GLuint;
 
 namespace polyvox_filament {
 
-class OpenGLTextureBuffer {
+class OpenGLTextureBuffer : public FlutterTextureBuffer {
   public:
-
     OpenGLTextureBuffer(
         flutter::PluginRegistrarWindows* pluginRegistrar,
         flutter::TextureRegistrar* textureRegistrar,
         std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result,
         uint32_t width,
         uint32_t height,
-        HGLRC context,
-        std::shared_ptr<std::mutex> renderMutex);
+        HGLRC context);
     
     ~OpenGLTextureBuffer();
     GLuint glTextureId = 0;
-    int64_t flutterTextureId = 0;
     std::unique_ptr<FlutterDesktopPixelBuffer> pixelBuffer;
     std::unique_ptr<uint8_t> pixelData;
     std::unique_ptr<flutter::TextureVariant> texture;
@@ -46,7 +45,6 @@ class OpenGLTextureBuffer {
     uint32_t _height = 0;
     HGLRC _context = NULL;
     bool logged = false;
-    std::shared_ptr<std::mutex> _renderMutex;
 };
 
 }