[gtk/cherry-pick-97bab27d] Merge branch 'fix-win32-empty-clipboard' into 'main'

[Chun-wei Fan <fanchunwei src gnome org>]

commit 15494640561a74cd1a3af7c4003b6a2d41511f95
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Apr 1 00:56:02 2022 +0000

    Merge branch 'fix-win32-empty-clipboard' into 'main'
    
    gdkclipboard-win32.c: Fix call to gdk_clipboard_claim_remote() (check GdkContentFormat is not NULL
    
    Closes #4796
    
    See merge request GNOME/gtk!4604
    
    (cherry picked from commit 97bab27d829c17a7ea796770f2e3c2a87fbc9850)
    
    8519ab56 gdkclipboard-win32.c: Fix call to gdk_clipboard_claim_remote()

 gdk/win32/gdkclipboard-win32.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
---
diff --git a/gdk/win32/gdkclipboard-win32.c b/gdk/win32/gdkclipboard-win32.c
index 36d56b8b53..ce80019e56 100644
--- a/gdk/win32/gdkclipboard-win32.c
+++ b/gdk/win32/gdkclipboard-win32.c
@@ -142,9 +142,13 @@ gdk_win32_clipboard_claim_remote (GdkWin32Clipboard *cb)
   cb->sequence_number = -1;
 
   formats = gdk_win32_clipboard_request_contentformats (cb);
-  gdk_clipboard_claim_remote (GDK_CLIPBOARD (cb), formats);
-  gdk_content_formats_unref (formats);
-  cb->sequence_number = GetClipboardSequenceNumber ();
+
+  if (formats != NULL)
+    {
+      gdk_clipboard_claim_remote (GDK_CLIPBOARD (cb), formats);
+      gdk_content_formats_unref (formats);
+      cb->sequence_number = GetClipboardSequenceNumber ();
+    }
 }
 
 static void