Util refactor and fix (#638)

* Remove unused functions

* Fix clone function not being visible on the window object

ext/bg/js/util.js

@@ -15,33 +15,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-function utilFunctionIsolate(func) {
-    return function isolatedFunction(...args) {
-        try {
-            args = args.map((v) => clone(v));
-            return func.call(this, ...args);
-        } catch (e) {
-            try {
-                String(func);
-            } catch (e2) {
-                // Dead object
-                return;
-            }
-            throw e;
-        }
-    };
-}
-
 function utilBackgroundIsolate(data) {
     const backgroundPage = chrome.extension.getBackgroundPage();
     return backgroundPage.clone(data);
 }
 
-function utilBackgroundFunctionIsolate(func) {
-    const backgroundPage = chrome.extension.getBackgroundPage();
-    return backgroundPage.utilFunctionIsolate(func);
-}
-
 function utilBackend() {
     const backend = chrome.extension.getBackgroundPage().yomichanBackend;
     if (!backend.isPrepared()) {

ext/mixed/js/core.js

@@ -192,6 +192,11 @@ const clone = (() => {
     return clone;
 })();
 
+// Expose clone function on the global object, since util.js's utilBackgroundIsolate needs access to it.
+if (typeof window === 'object' && window !== null) {
+    window.clone = clone;
+}
+
 
 /*
  * Async utilities