Drop QOffscreenSurface guard

Summary:
Given that our QPA now creates native offscreen surfaces, we no longer
need the QOffscreenSurface guard introduced by 61956025f.

Reviewers: #kwin, romangg

Reviewed By: #kwin, romangg

Subscribers: romangg, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D22198

internal_client.cpp

@@ -37,19 +37,7 @@ InternalClient::InternalClient(KWayland::Server::ShellSurfaceInterface *surface)
 {
     findInternalWindow();
     updateInternalWindowGeometry();
-
+    updateDecoration(true);
-    // Qt asks our QPA to create a platform window for each QOffscreenSurface.
-    // Given that those windows aren't toplevels, findInternalWindow may not be
-    // able to find corresponding QWindow object for this client, which means
-    // no-border and pretty much every other property that depends on QWindow
-    // flags will have undefined value. Unfortunately the Aurorae decoration
-    // engine creates three internal clients per each decoration. One of those
-    // clients represents QOffscreenSurface. Thus we have to ensure that the
-    // QOffscreenSurface client is not decorated, otherwise kwin will fall
-    // into an infinite "recursion."
-    if (m_internalWindow) {
-        updateDecoration(true);
-    }
 }
 
 InternalClient::InternalClient(KWayland::Server::XdgShellSurfaceInterface *surface)
@@ -94,6 +82,8 @@ void InternalClient::findInternalWindow()
         m_internalWindow->installEventFilter(this);
         return;
     }
+
+    qCWarning(KWIN_CORE, "Couldn't find an internal window for surface with id %x", surface()->id());
 }
 
 bool InternalClient::eventFilter(QObject *watched, QEvent *event)