Remove some premature optimisation

Reduces header dependencies.
diff --git a/vncviewer/DesktopWindow.cxx b/vncviewer/DesktopWindow.cxx
index 40d08ae..2a2f873 100644
--- a/vncviewer/DesktopWindow.cxx
+++ b/vncviewer/DesktopWindow.cxx
@@ -34,7 +34,9 @@
 #include "parameters.h"
 #include "vncviewer.h"
 #include "CConn.h"
+#include "Viewport.h"
 
+#include <FL/Fl.H>
 #include <FL/Fl_Scroll.H>
 #include <FL/x.H>
 
@@ -220,6 +222,26 @@
   viewport->setColourMapEntries(firstColour, nColours, rgbs);
 }
 
+void DesktopWindow::fillRect(const rfb::Rect& r, rfb::Pixel pix) {
+  viewport->fillRect(r, pix);
+}
+
+void DesktopWindow::imageRect(const rfb::Rect& r, void* pixels) {
+  viewport->imageRect(r, pixels);
+}
+
+void DesktopWindow::copyRect(const rfb::Rect& r, int srcX, int srcY) {
+  viewport->copyRect(r, srcX, srcY);
+}
+
+rdr::U8* DesktopWindow::getBufferRW(const rfb::Rect& r, int* stride) {
+  return viewport->getBufferRW(r, stride);
+}
+
+void DesktopWindow::damageRect(const rfb::Rect& r) {
+  viewport->damageRect(r);
+}
+
 
 // Copy the areas of the framebuffer that have been changed (damaged)
 // to the displayed window.