Setting permissions are flaky in firefox

[JoelEinbinder]

It looks like the permissions onchange event is fired asynchronously after we set the permission in firefox. This causes the permission.spec.js test "should trigger permission onchange" to be flaky. It flakes for me about 1/1000 times locally, and very frequently on the bots.

[JoelEinbinder]

I was debating whether the feature is flaky, or the test needs to be changed. But I would expect Browser.grantPermissions to wait until all pages have received the new permissions.

[JoelEinbinder]

Long running test to repro:

      await page.goto(server.EMPTY_PAGE);
      await page.evaluate(() => {
        window['state'] = null;
        return navigator.permissions.query({name: 'geolocation'}).then(function(result) {
          window['state'] = result.state;
          result.onchange = function() {
            window['state'] = result.state;
          };
        });
      });
      for (var i = 0; i < 5000; i++) {
        console.log(i);
        await context.setPermissions(server.EMPTY_PAGE, []);
        expect(await page.evaluate(() => window['state'])).toEqual('denied');
        await context.setPermissions(server.EMPTY_PAGE, ['geolocation']);
        expect(await page.evaluate(() => window['state'])).toEqual('granted');
      }

use TIMEOUT=0

Also it seems to take firefox a long time to close, which is dependent on how long I make the loop. Maybe we have a leak?