Track xwayland buffer scale in X11Window

It can happen that when the xwayland scale factor changes, the logical geometry
will remain the same, but the x windows still need to reconfigured to update the
native geometry.

In order to address that, this change makes X11Window track the buffer scale
so if the logical geometry is the same, the x windows will be still reconfigured
with the new xwayland scale.

src/x11window.cpp

@@ -4359,8 +4359,9 @@ void X11Window::moveResizeInternal(const QRectF &rect, MoveResizeMode mode)
         clientGeometry = frameRectToClientRect(frameGeometry);
     }
     const QRectF bufferGeometry = frameRectToBufferRect(frameGeometry);
+    const qreal bufferScale = kwinApp()->xwaylandScale();
 
-    if (m_bufferGeometry == bufferGeometry && m_clientGeometry == clientGeometry && m_frameGeometry == frameGeometry) {
+    if (m_bufferGeometry == bufferGeometry && m_clientGeometry == clientGeometry && m_frameGeometry == frameGeometry && m_bufferScale == bufferScale) {
         return;
     }
 
@@ -4374,6 +4375,7 @@ void X11Window::moveResizeInternal(const QRectF &rect, MoveResizeMode mode)
     m_frameGeometry = frameGeometry;
     m_clientGeometry = clientGeometry;
     m_bufferGeometry = bufferGeometry;
+    m_bufferScale = bufferScale;
     m_output = workspace()->outputAt(frameGeometry.center());
 
     if (!areGeometryUpdatesBlocked()) {

src/x11window.h

@@ -442,6 +442,7 @@ private:
     Xcb::Window m_client;
     Xcb::Window m_wrapper;
     Xcb::Window m_frame;
+    qreal m_bufferScale = 1;
     xcb_window_t m_wmClientLeader = XCB_WINDOW_NONE;
     int m_activityUpdatesBlocked;
     bool m_blockedActivityUpdatesRequireTransients;