check if the user is running brave browser

www/common/cryptpad-common.js

@@ -1135,6 +1135,31 @@ define([
             window.RTCPeerConnection);
     };
 
+    common.isBrave = function () { // Courtesy of https://www.ctrl.blog/entry/brave-user-agent-detection
+        try {
+            // initial assertions
+            if (!window.google_onload_fired && navigator.userAgent && !navigator.userAgent.includes('Chrome')) {
+                return false;
+            }
+
+            // set up test
+            var test = document.createElement('iframe');
+            test.style.display = 'none';
+            document.body.appendChild(test);
+
+            // empty frames only have this attribute set in Brave Shield
+            var is_brave = (test.contentWindow.google_onload_fired === true);
+
+            // teardown test
+            test.parentNode.removeChild(test);
+
+            return is_brave;
+        } catch (e) { // just in case...
+            console.error(e);
+            return false;
+        }
+    };
+
     common.ready = (function () {
         var env = {};
         var initialized = false;
@@ -1182,6 +1207,10 @@ define([
                 Feedback.send('NO_CSS_VARIABLES');
             }
 
+            if (common.isBrave()) {
+                Feedback.send('BRAVE_BROWSER');
+            }
+
             Feedback.reportScreenDimensions();
             Feedback.reportLanguage();
         };