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According to latest editor's draft http://rawgit.com/w3c/html-api-map/master/index.html
meter tag should have MSAA+IA2 Role as ROLE_SYSTEM_PROGRESSBAR.
And for mac, the AX Mappings should be copy of ARIA role progressbar.

This CL depends on https://codereview.chromium.org/652663003/

This CL also takes care of small fixes related with details tag and div tag.

BUG=421376

Review URL: https://codereview.chromium.org/657513002

Cr-Commit-Position: refs/heads/master@{#299944}