scene: Drop SceneOpenGL::openGLPlatformInterfaceExtensions()

It doesn't belong in the Scene, whose sole responsibility is to draw
windows.

src/debug_console.cpp

@@ -13,7 +13,7 @@
 #include "internalwindow.h"
 #include "keyboard_input.h"
 #include "main.h"
-#include "scene/scene.h"
+#include "platformsupport/scenes/opengl/openglbackend.h"
 #include "unmanaged.h"
 #include "utils/filedescriptor.h"
 #include "utils/subsurfacemonitor.h"
@@ -683,7 +683,8 @@ void DebugConsole::initGLTab()
         return text;
     };
 
-    m_ui->platformExtensionsLabel->setText(extensionsString(Compositor::self()->scene()->openGLPlatformInterfaceExtensions()));
+    const OpenGLBackend *backend = static_cast<OpenGLBackend *>(Compositor::self()->backend());
+    m_ui->platformExtensionsLabel->setText(extensionsString(backend->extensions()));
     m_ui->openGLExtensionsLabel->setText(extensionsString(openGLExtensions()));
 }
 

src/scene/scene.cpp

@@ -603,9 +603,4 @@ bool Scene::supportsNativeFence() const
     return false;
 }
 
-QVector<QByteArray> Scene::openGLPlatformInterfaceExtensions() const
-{
-    return QVector<QByteArray>{};
-}
-
 } // namespace

src/scene/scene.h

@@ -136,15 +136,6 @@ public:
      */
     virtual bool animationsSupported() const = 0;
 
-    /**
-     * The backend specific extensions (e.g. EGL/GLX extensions).
-     *
-     * Not the OpenGL (ES) extension!
-     *
-     * Default implementation returns empty list
-     */
-    virtual QVector<QByteArray> openGLPlatformInterfaceExtensions() const;
-
     virtual std::shared_ptr<GLTexture> textureForOutput(Output *output) const
     {
         return {};

src/scene/scene_opengl.cpp

@@ -84,11 +84,6 @@ bool SceneOpenGL::animationsSupported() const
     return !GLPlatform::instance()->isSoftwareEmulation();
 }
 
-QVector<QByteArray> SceneOpenGL::openGLPlatformInterfaceExtensions() const
-{
-    return m_backend->extensions().toVector();
-}
-
 std::shared_ptr<GLTexture> SceneOpenGL::textureForOutput(Output *output) const
 {
     return m_backend->textureForOutput(output);

src/scene/scene_opengl.h

@@ -42,7 +42,6 @@ public:
         return m_backend;
     }
 
-    QVector<QByteArray> openGLPlatformInterfaceExtensions() const override;
     std::shared_ptr<GLTexture> textureForOutput(Output *output) const override;
 
 private: