[mv3] Add ability to reset to default settings

platform/mv3/extension/_locales/en/messages.json

@@ -383,6 +383,14 @@
     "message": "Restore…",
     "description": "Text for buttons used to restore content"
   },
+  "resetToDefaultButton": {
+    "message": "Reset to default settings…",
+    "description": "Text for buttons used to reset configurations to default"
+  },
+  "resetToDefaultConfirm": {
+    "message": "All your custom settings will be removed. Do you really want to reset to default settings?",
+    "description": "Message asking user to confirm reset to default settings"
+  },
   "dnrRulesWarning": {
     "message": "Do not add content from untrusted sources",
     "description": "Short description of the DNR rules editor pane"

platform/mv3/extension/dashboard.html

@@ -103,6 +103,7 @@
             <p>
                 <button class="iconified dontshrink" type="button"><span class="fa-icon">download-alt</span><span data-i18n="backupButton">_</span><span class="hover"></span></button>
                 <button class="iconified dontshrink" type="button"><span class="fa-icon">upload-alt</span><span data-i18n="restoreButton">_</span><span class="hover"></span></button><input type="file" accept="application/json">
+                <button class="iconified dontshrink" type="button"><span class="fa-icon">undo</span><span data-i18n="resetToDefaultButton">_</span><span class="hover"></span></button><input type="file" accept="application/json">
             </p>
         </div>
     </section>

platform/mv3/extension/js/settings.js

@@ -19,7 +19,7 @@
     Home: https://github.com/gorhill/uBlock
 */
 
-import { browser, sendMessage } from './ext.js';
+import { browser, i18n, sendMessage } from './ext.js';
 import { dom, qs$ } from './dom.js';
 import { hashFromIterable } from './dashboard.js';
 import { renderFilterLists } from './filter-lists.js';
@@ -173,6 +173,13 @@ async function restoreSettings() {
     input.click();
 }
 
+async function resetSettings() {
+    const response = self.confirm(i18n.getMessage('resetToDefaultConfirm'));
+    if ( response !== true ) { return; }
+    const api = await import('./backup-restore.js');
+    await api.restoreFromObject({});
+}
+
 /******************************************************************************/
 
 dom.on('#autoReload input[type="checkbox"]', 'change', ev => {
@@ -210,6 +217,10 @@ dom.on('section[data-pane="settings"] [data-i18n="restoreButton"]', 'click', ( )
     restoreSettings();
 });
 
+dom.on('section[data-pane="settings"] [data-i18n="resetToDefaultButton"]', 'click', ( ) => {
+    resetSettings();
+});
+
 /******************************************************************************/
 
 function listen() {