feat(chromium): roll Chromium to r705776

This corresponds to Chromium 79.0.3942.0.

This roll includes:

- Support CSS media feature emulation in CDP
  https://chromium-review.googlesource.com/c/chromium/src/+/1821608
- Implement timezone ID verification
  https://chromium-review.googlesource.com/c/chromium/src/+/1822557
- Allow aria-hidden objects into the browser-side ax tree
  https://chromium-review.googlesource.com/c/chromium/src/+/1760862

package.json

@@ -8,7 +8,7 @@
     "node": ">=8.16.0"
   },
   "puppeteer": {
-    "chromium_revision": "686378"
+    "chromium_revision": "705776"
   },
   "scripts": {
     "unit": "node test/test.js",

test/accessibility.spec.js

@@ -71,6 +71,7 @@ module.exports.addTests = function({testRunner, expect, FFOX}) {
           {role: 'textbox', name: 'Input with whitespace', value: '  '},
           {role: 'textbox', name: '', value: 'value only'},
           {role: 'textbox', name: 'placeholder', value: 'and a value'},
+          {role: 'text', name: 'This is a description!'},
           {role: 'textbox', name: 'placeholder', value: 'and a value', description: 'This is a description!'},
           {role: 'combobox', name: '', value: 'First Option', children: [
             {role: 'menuitem', name: 'First Option', selected: true},

test/coverage.spec.js

@@ -85,6 +85,7 @@ module.exports.addTests = function({testRunner, expect}) {
       expect(coverage.length).toBe(1);
       const entry = coverage[0];
       expect(entry.url).toContain('unused.html');
+      // Broken because of https://bugs.chromium.org/p/v8/issues/detail?id=9857
       expect(entry.ranges.length).toBe(0);
     });
     it('should work with conditionals', async function({page, server}) {