Fix bug with displaying browser extension icon

Resolves issue #1391 by updating `browserAction` to `action` and changing `document.createElement('canvas')` to `new offscreenCanvas(200, 200);`

5-browser-extension/3-background-tasks-and-performance/README.md

@@ -115,12 +115,12 @@ And finally, in `/dist/background.js`, add the listener for these background act
 ```JavaScript
 chrome.runtime.onMessage.addListener(function (msg, sender, sendResponse) {
 	if (msg.action === 'updateIcon') {
-		chrome.browserAction.setIcon({ imageData: drawIcon(msg.value) });
+		chrome.action.setIcon({ imageData: drawIcon(msg.value) });
 	}
 });
 //borrowed from energy lollipop extension, nice feature!
 function drawIcon(value) {
-	let canvas = document.createElement('canvas');
+	let canvas = new OffscreenCanvas(200, 200);
 	let context = canvas.getContext('2d');
 
 	context.beginPath();

5-browser-extension/solution/dist/background.js

@@ -1,11 +1,11 @@
 chrome.runtime.onMessage.addListener(function (msg, sender, sendResponse) {
 	if (msg.action === 'updateIcon') {
-		chrome.browserAction.setIcon({ imageData: drawIcon(msg.value) });
+		chrome.action.setIcon({ imageData: drawIcon(msg.value) });
 	}
 });
 //borrowed from energy lollipop extension, nice feature!
 function drawIcon(value) {
-	let canvas = document.createElement('canvas');
+	let canvas = new OffscreenCanvas(200, 200);
 	let context = canvas.getContext('2d');
 
 	context.beginPath();