From 245e71ae8de3f4b5f3478739be819981bb12dfab Mon Sep 17 00:00:00 2001
From: Alexander Dunaev <adunaev@igalia.com>
Date: Sat, 13 Nov 2021 06:35:35 +0000
Subject: [PATCH] [linux/xfce] Introduced a hack for Xfwm.

This proposes an alternative to [1].  Either this patch or that one
should be landed, but not both.  See the linked crbug for the details.

Setting the frame extents via the _GTK_FRAME_EXTENTS property turned out
to be problematic at Xfwm.  While the issue is agreed to be a bug in the
window manager, for now we disable setting the frame extents on that WM.

This patch introduces a logic that disables setting the window property
on Xfwm.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/3275653

Bug: 1260821
Change-Id: I4b734ac0dc2b97d7ed6b1842564a33ec6e4b4035
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3275272
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Alexander Dunaev <adunaev@igalia.com>
Cr-Commit-Position: refs/heads/main@{#941444}
---

diff --git a/ui/platform_window/x11/x11_window.cc b/ui/platform_window/x11/x11_window.cc
index 2b20835..4fa2992 100644
--- a/ui/platform_window/x11/x11_window.cc
+++ b/ui/platform_window/x11/x11_window.cc
@@ -1016,6 +1016,21 @@
 }
 
 bool X11Window::CanSetDecorationInsets() const {
+  // Xfwm handles _GTK_FRAME_EXTENTS a bit unexpected way.  That is a known bug
+  // that will be eventually fixed, but for now we have to disable the function
+  // for Xfce.  The block below should be removed when Xfwm is updated with the
+  // fix and is known to work properly.
+  // See https://crbug.com/1260821.
+  {
+    static WindowManagerName wm_name = WM_OTHER;
+    static bool checked_for_wm = false;
+    if (!checked_for_wm) {
+      wm_name = GuessWindowManager();
+      checked_for_wm = true;
+    }
+    if (wm_name == WM_XFWM4)
+      return false;
+  }
   return ui::WmSupportsHint(x11::GetAtom("_GTK_FRAME_EXTENTS"));
 }