Implement ShadowRoot.delegatesFocus 4/4 (match CSS :focus for shadow host)

LayoutTests/fast/dom/shadow/focus-shadowhost-display-none-expected.txt

Index: LayoutTests/fast/dom/shadow/focus-shadowhost-display-none-expected.txt
diff --git a/LayoutTests/fast/dom/shadow/focus-shadowhost-display-none-expected.txt b/LayoutTests/fast/dom/shadow/focus-shadowhost-display-none-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..5beb3af59180c81fd60f50be6d9030354630fb99
--- /dev/null
+++ b/LayoutTests/fast/dom/shadow/focus-shadowhost-display-none-expected.txt
@@ -0,0 +1,23 @@
+Check if shadow host with display:none CSS rule for :focus works. crbug.com/482830
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+when shadow host itself is focused, it should match display:none, lose focus then becomes display:block again.
+PASS window.getComputedStyle(host).display is "none"
+PASS document.activeElement is host
+PASS root.activeElement is null
+PASS successfullyParsed is true
+
+TEST COMPLETE
+PASS window.getComputedStyle(host).display is "block"
+PASS document.activeElement is document.body
+PASS root.activeElement is null
+when shadow host with delegatesFocus=true has focused element inside the shadow, it should also match display:none, then lose focus and become display:block again.
+PASS window.getComputedStyle(host).display is "none"
+PASS document.activeElement is host
+PASS root.activeElement is input
+PASS window.getComputedStyle(host).display is "block"
+PASS document.activeElement is document.body
+PASS root.activeElement is null
+