Drop SurfacePixmap::contentsRect()

It's unused.

src/surfaceitem.cpp

@@ -193,11 +193,6 @@ QSize SurfacePixmap::size() const
     return m_size;
 }
 
-QRectF SurfacePixmap::contentsRect() const
-{
-    return m_contentsRect;
-}
-
 bool SurfacePixmap::isDiscarded() const
 {
     return m_isDiscarded;

src/surfaceitem.h

@@ -80,7 +80,6 @@ public:
 
     bool hasAlphaChannel() const;
     QSize size() const;
-    QRectF contentsRect() const;
 
     bool isDiscarded() const;
     void markAsDiscarded();
@@ -92,7 +91,6 @@ public:
 
 protected:
     QSize m_size;
-    QRectF m_contentsRect;
     bool m_hasAlphaChannel = false;
 
 private:

src/surfaceitem_x11.cpp

@@ -239,7 +239,6 @@ void SurfacePixmapX11::create()
     // this class is only used on X11 where the logical size and
     // device pixel size is guaranteed to be the same and we can convert safely
     m_size = bufferGeometry.size().toSize();
-    m_contentsRect = QRectF(window->clientPos(), window->clientSize());
 }
 
 } // namespace KWin