Gamepad: make gamepad events play well with page visibility

LayoutTests/gamepad/page-visibility-expected.txt

Index: LayoutTests/gamepad/page-visibility-expected.txt
diff --git a/LayoutTests/gamepad/page-visibility-expected.txt b/LayoutTests/gamepad/page-visibility-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..6eb4e2a69ff4cacadf6396262ba88b9386f67ffa
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+++ b/LayoutTests/gamepad/page-visibility-expected.txt
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+Tests that gamepad events are not fired when page is hidden but kept as pending and fired when the page becomes visible again.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS Received a gamepadconnected event
+PASS event.gamepad.index is 0
+PASS document.visibilityState is "hidden"
+PASS eventCounter < expectations.length is true
+PASS event.gamepad.index is 0
+PASS expected.connected is false
+PASS event.gamepad.connected is false
+PASS eventCounter < expectations.length is true
+PASS event.gamepad.index is 1
+PASS expected.connected is false
+PASS event.gamepad.connected is false
+PASS event.gamepad.id is "old"
+PASS eventCounter < expectations.length is true
+PASS event.gamepad.index is 1
+PASS expected.connected is true
+PASS event.gamepad.connected is true
+PASS event.gamepad.id is "new"
+PASS eventCounter < expectations.length is true
+PASS event.gamepad.index is 2
+PASS expected.connected is true
+PASS event.gamepad.connected is true
+PASS successfullyParsed is true
+
+TEST COMPLETE
+