fix(webkit): rewrite global object retrieval errors (#640)

Author: dgozman

src/webkit/wkExecutionContext.ts

@@ -111,7 +111,15 @@ export class WKExecutionContext implements js.ExecutionContextDelegate {
       serializableArgs = args;
     }
 
-    const thisObjectId = await this._contextGlobalObjectId();
+    let thisObjectId;
+    try {
+      thisObjectId = await this._contextGlobalObjectId();
+    } catch (error) {
+      if (error.message.includes('Missing injected script for given'))
+        throw new Error('Execution context was destroyed, most likely because of a navigation.');
+      throw error;
+    }
+
     let callFunctionOnPromise;
     try {
       callFunctionOnPromise = this._session.send('Runtime.callFunctionOn', {

test/screenshot.spec.js

@@ -181,8 +181,8 @@ module.exports.describe = function({testRunner, expect, product, FFOX, CHROMIUM,
       const screenshot = await page.screenshot();
       expect(screenshot).toBeGolden('screenshot-webgl.png');
     });
-    // firefox and webkit are flaky
-    it.skip(FFOX || WEBKIT)('should work while navigating', async({page, server}) => {
+    // firefox is flaky
+    it.skip(FFOX)('should work while navigating', async({page, server}) => {
       await page.setViewport({width: 500, height: 500});
       await page.goto(server.PREFIX + '/redirectloop1.html');
       for (let i = 0; i < 10; i++) {