mi: Shortcut miDoCopy/miCopyArea based on clipList

This is maybe one more comparison, but it catches FullyObscured windows
slightly earlier, so it's kind of a wash. The important thing is this
allows for paintable but unmapped windows, which will have non-empty
clipList.

mi/mibitblt.c

@@ -92,9 +92,9 @@ miCopyArea(DrawablePtr pSrcDrawable,
     srcx = xIn + pSrcDrawable->x;
     srcy = yIn + pSrcDrawable->y;
 
-    /* If the destination isn't realized, this is easy */
+    /* If the destination is clipped away, this is easy */
     if (pDstDrawable->type == DRAWABLE_WINDOW &&
-        !((WindowPtr) pDstDrawable)->realized)
+        RegionNil(&((WindowPtr)pDstDrawable)->clipList))
         return NULL;
 
     /* clip the source */

mi/micopy.c

@@ -152,10 +152,9 @@ miDoCopy(DrawablePtr pSrcDrawable,
     Bool fastDst = FALSE;       /* for fast clipping with one rect dest */
     Bool fastExpose = FALSE;    /* for fast exposures with pixmap source */
 
-    /* Short cut for unmapped windows */
-
+    /* Short cut for unmapped or fully clipped windows */
     if (pDstDrawable->type == DRAWABLE_WINDOW &&
-        !((WindowPtr) pDstDrawable)->realized) {
+        RegionNil(&((WindowPtr)pDstDrawable)->clipList)) {
         return NULL;
     }