When resizing a window with redirected descendents, don't expose them

Bit/window gravity computations need to recompute exposures to manage the
bits which are saved by gravity during the resize computation. That's easy
for non-redirected windows where the bits are all within the parent's
pixmap. For redirected windows, we don't need to deal with this at all, so
just skip the whole re-computation adventure.

Signed-off-by: Keith Packard <keithp@keithp.com>

mi/miwindow.c

@@ -342,6 +342,15 @@ miRecomputeExposures (
 
     if (pWin->valdata)
     {
+#ifdef COMPOSITE
+	/*
+	 * Redirected windows are not affected by parent window
+	 * gravity manipulations, so don't recompute their
+	 * exposed areas here.
+	 */
+	if (pWin->redirectDraw != RedirectDrawNone)
+	    return WT_DONTWALKCHILDREN;
+#endif
 	pScreen = pWin->drawable.pScreen;
 	/*
 	 * compute exposed regions of this window