Replaced dev/Common/ClientStorageDriver/* with webstorage polyfill

Cleanup some other code

dev/polyfill.js

@@ -1,3 +1,4 @@
+(w=>{
 
 Array.prototype.flat || Object.defineProperty(Array.prototype, 'flat', {
 	configurable: true,
@@ -15,18 +16,47 @@ Array.prototype.flat || Object.defineProperty(Array.prototype, 'flat', {
 	writable: true
 });
 
-if (!window.ResizeObserver) {
-	window.ResizeObserver = class {
-		constructor(callback) {
-			this.observer = new MutationObserver(callback.debounce(250));
-		}
+w.ResizeObserver || (w.ResizeObserver = class {
+	constructor(callback) {
+		this.observer = new MutationObserver(callback.debounce(250));
+	}
 
-		disconnect() {
-			this.observer.disconnect();
-		}
+	disconnect() {
+		this.observer.disconnect();
+	}
 
-		observe(target) {
-			this.observer.observe(target, { attributes: true, subtree: true, attributeFilter: ['style'] });
-		}
-	};
-}
+	observe(target) {
+		this.observer.observe(target, { attributes: true, subtree: true, attributeFilter: ['style'] });
+	}
+});
+
+const Storage = type => {
+	let name = type+'Storage';
+	try {
+		w[name].setItem('storage', '');
+		w[name].getItem('storage');
+		w[name].removeItem('storage');
+	} catch (e) {
+		console.error(e);
+		const cookieName = encodeURIComponent(name+('session' === type ? w.name || (w.name = Date.now()) : ''));
+
+		// initialise if there's already data
+		let data = document.cookie.match('(^|;) ?'+cookieName+'=([^;]*)(;|$)');
+		data = data ? decodeURIComponent(data[2]) : null;
+		data = data ? JSON.parse(data) : {};
+
+		w[name] = {
+			getItem: key => data[key] === undefined ? null : data[key],
+			setItem: function (key, value) {
+				data[key] = ''+value; // forces the value to a string
+				document.cookie = cookieName+'='+encodeURIComponent(JSON.stringify(data))
+					+"; expires="+('local' === type ? (new Date(Date.now()+(365*24*60*60*1000))).toGMTString() : '')
+					+"; path=/; samesite=strict";
+			}
+		};
+	}
+};
+Storage('local');
+Storage('session');
+
+})(window);