master f91c9dd2b4: Remove some unneeded tests from the X double buffering code

[Po Lu]

branch: master
commit f91c9dd2b4e8156217b20f8658a2862e1009a27f
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Remove some unneeded tests from the X double buffering code
    
    * src/xterm.c (x_flip_and_flush): Fix coding style.
    (flush_dirty_back_buffer_on): Avoid testing for impossible
    situations.
---
 src/xterm.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 98641d0241..cce586952a 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -5468,7 +5468,7 @@ x_flip_and_flush (struct frame *f)
 {
   block_input ();
   if (FRAME_X_NEED_BUFFER_FLIP (f))
-      show_back_buffer (f);
+    show_back_buffer (f);
   x_flush (f);
   unblock_input ();
 }
@@ -13673,12 +13673,9 @@ static void
 flush_dirty_back_buffer_on (struct frame *f)
 {
   block_input ();
-  if (FRAME_LIVE_P (f) &&
-      FRAME_X_P (f) &&
-      FRAME_X_WINDOW (f) &&
-      !FRAME_GARBAGED_P (f) &&
-      !buffer_flipping_blocked_p () &&
-      FRAME_X_NEED_BUFFER_FLIP (f))
+  if (!FRAME_GARBAGED_P (f)
+      && !buffer_flipping_blocked_p ()
+      && FRAME_X_NEED_BUFFER_FLIP (f))
     show_back_buffer (f);
   unblock_input ();
 }