Fix conflict with Googel Drive (fix #621)

lib/single-file/processors/hooks/content/content-hooks-frames.js

@@ -119,6 +119,8 @@ function loadDeferredImagesResetZoomLevel(options) {
 
 function injectedScript() {
 	const console = globalThis.console;
+	const CustomEvent = globalThis.CustomEvent;
+	const dispatchEvent = event => globalThis.dispatchEvent(event);
 	const warn = (console && console.warn && ((...args) => console.warn(...args))) || (() => { });
 	const NEW_FONT_FACE_EVENT = "single-file-new-font-face";
 	const FONT_STYLE_PROPERTIES = {