Revert of Forward BrowserAccessibility get_accState to AXPlatformNode. (patchset #5 id:80001 of https://codereview.chromium.org/2913553002/ )

Reason for revert:
READONLY state missing, breaks screen reader virtual buffers

Original issue's description:
> Forward BrowserAccessibility get_accState to AXPlatformNode.
>
> This is another migration from BrowserAccessibility to AXPlatformNodeWin.
> In this installment, we're converting get_accState. This one is mostly
> straightforward. The one gotcha is that there are some types that need
> to be explictly marked as focusable if they are selectable.
>
> BUG=703369
>
> Review-Url: https://codereview.chromium.org/2913553002
> Cr-Commit-Position: refs/heads/master@{#478110}
> Committed: https://chromium.googlesource.com/chromium/src/+/2396b649beff6d478edff6334af2305418cc3c45

TBR=dougt@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=703369,733313

Review-Url: https://codereview.chromium.org/2937083002
Cr-Commit-Position: refs/heads/master@{#479448}
12 files changed