Output selected state for genericContainer and heading

In ARC++ accessibility, some nodes of generic container or heading role
can have a selected state, but it was not announced by ChromeVox.

This CL adds an output of selected status.

Bug: b:130186975
Test: still passes browser_tests --gtest_filter="ChromeVoxOutputE2ETest*"
Change-Id: I53d9babacb5696802dc36b2adaf212d1116d0047
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1905291Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Sara Kato <sarakato@chromium.org>
Commit-Queue: Hiroki Sato <hirokisato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#716091}

chrome/browser/resources/chromeos/chromevox/background/output.js

@@ -439,8 +439,10 @@ Output.RULES = {
     date: {enter: `$nameFromNode $role $state $restriction $description`},
     dialog: {enter: `$nameFromNode $role $description`},
     genericContainer: {
-      enter: `$nameFromNode $description $state`,
-      speak: `$nameOrTextContent $description $state`
+      enter: `$nameFromNode $description $state
+          $if($selected, @aria_selected_true)`,
+      speak: `$nameOrTextContent $description $state
+          $if($selected, @aria_selected_true)`
     },
     embeddedObject: {speak: `$name`},
     grid: {
@@ -457,11 +459,11 @@ Output.RULES = {
       enter: `!relativePitch(hierarchicalLevel)
           $nameFromNode=
           $if($hierarchicalLevel, @tag_h+$hierarchicalLevel, $role) $state
-          $description`,
+          $description $if($selected, @aria_selected_true)`,
       speak: `!relativePitch(hierarchicalLevel)
           $nameOrDescendants=
           $if($hierarchicalLevel, @tag_h+$hierarchicalLevel, $role) $state
-          $restriction $description`
+          $restriction $description $if($selected, @aria_selected_true)`
     },
     image: {
       speak: `$if($name, $name,