Make Compositor responsible for syncing the GlStrictBinding flag

The GlStrictBinding flag indicates whether it's okay not to re-bind the X11
pixmap to the OpenGL surface texture if the corresponding window is damaged.
It doesn't really affect the SceneOpenGL, only low level backend stuff.

src/composite.cpp

@@ -34,6 +34,7 @@
 #include "x11syncmanager.h"
 #include "xcbutils.h"
 
+#include <kwinglplatform.h>
 #include <kwingltexture.h>
 
 #include <KWaylandServer/surface_interface.h>
@@ -192,6 +193,11 @@ bool Compositor::attemptOpenGLCompositing()
     m_backend = backend.take();
     m_scene = scene.take();
 
+    // set strict binding
+    if (options->isGlStrictBindingFollowsDriver()) {
+        options->setGlStrictBinding(!GLPlatform::instance()->supports(LooseBinding));
+    }
+
     qCDebug(KWIN_CORE) << "OpenGL compositing has been successfully initialized";
     return true;
 }

src/scenes/opengl/scene_opengl.cpp

@@ -96,11 +96,6 @@ SceneOpenGL::SceneOpenGL(OpenGLBackend *backend, QObject *parent)
         glBindVertexArray(vao);
     }
 
-    // set strict binding
-    if (options->isGlStrictBindingFollowsDriver()) {
-        options->setGlStrictBinding(!glPlatform->supports(LooseBinding));
-    }
-
     qCDebug(KWIN_OPENGL) << "OpenGL 2 compositing successfully initialized";
 }