Handle broken Oculus browser keyboard events

It sets KeyboardEvent.key to "Unidentified" for all non-character keys,
which means we must ignore it and use the legacy handling to figure out
the key pressed.

core/input/util.js

@@ -67,7 +67,7 @@ export function getKeycode(evt) {
 // Get 'KeyboardEvent.key', handling legacy browsers
 export function getKey(evt) {
     // Are we getting a proper key value?
-    if (evt.key !== undefined) {
+    if ((evt.key !== undefined) && (evt.key !== 'Unidentified')) {
         // Mozilla isn't fully in sync with the spec yet
         switch (evt.key) {
             case 'OS': return 'Meta';

tests/test.helper.js

@@ -108,6 +108,8 @@ describe('Helpers', function () {
         });
         it('should use charCode if no key', function () {
             expect(KeyboardUtil.getKey({charCode: 'Š'.charCodeAt(), keyCode: 0x42, which: 0x43})).to.be.equal('Š');
+            // Broken Oculus browser
+            expect(KeyboardUtil.getKey({charCode: 'Š'.charCodeAt(), keyCode: 0x42, which: 0x43, key: 'Unidentified'})).to.be.equal('Š');
         });
         it('should return Unidentified when it cannot map the key', function () {
             expect(KeyboardUtil.getKey({keycode: 0x42})).to.be.equal('Unidentified');