ARIA role region is not exposed correct with MSAA+IA2 role

According to specs, ARIA role region should be exposed as below

MSAA+IA2: ROLE_SYSTEM_PANE

AXRole:AXGroup
AXSubrole:AXDocumentRegion
AXRoleDescription:'region'

Also section tag should have AXRoleDescription as 'region'

BUG=424521
TBR=avi

Review URL: https://codereview.chromium.org/638103003

Cr-Commit-Position: refs/heads/master@{#300535}
17 files changed