This patch makes AXMenuListOption respect role attribute.

Because AXMenuListOption is a type of AXMockObject,
it can't have determineAccessibilityRole() from AXNodeObject
and role attribute is checked at roleValue().

BUG=467434

Review URL: https://codereview.chromium.org/1561533003

Cr-Commit-Position: refs/heads/master@{#370336}
4 files changed