[chrome-gnome-shell] Don't use InstallTrigger to detect Firefox.

[Yuri Konotopov <ykonotopov src gnome org>]

commit 7052637ca0502e1967515992ecb87c303f009a49
Author: Emilio Cobos Álvarez <emilio crisal io>
Date:   Wed Jun 22 22:17:56 2022 +0200

    Don't use InstallTrigger to detect Firefox.

 extension/include/compat-content-script.js | 2 +-
 extension/include/constants.js             | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/extension/include/compat-content-script.js b/extension/include/compat-content-script.js
index ee1ec25..a7ef3a5 100644
--- a/extension/include/compat-content-script.js
+++ b/extension/include/compat-content-script.js
@@ -8,7 +8,7 @@
     (at your option) any later version.
  */
 
-if(COMPAT.IS_FIREFOX)
+if(!window.chrome)
 {
        (function() {
                // Define the API subset provided to the webpage
diff --git a/extension/include/constants.js b/extension/include/constants.js
index 211ebf1..f48d514 100644
--- a/extension/include/constants.js
+++ b/extension/include/constants.js
@@ -12,7 +12,7 @@ GS_CHROME_ID                          = chrome.runtime.id;
 PLATFORMS_WHITELIST                    = ["freebsd", "linux", "openbsd"];
 
 COMPAT = {
-       IS_FIREFOX:      (typeof(InstallTrigger) !== 'undefined'),
+       IS_FIREFOX:      CSS.supports("-moz-appearance: none"),
        IS_OPERA:        navigator.userAgent.indexOf(' OPR/') >= 0
 };