Forward 4 methods from BrowserAccessibilityComWin to AXPlatformNodeWin

Continuing on removing stuff from the browser side, this CL forwards four
more methods to the platform node side:

get_attributes, get_uniqueID, get_windowHandle, get_indexInParent

Bug: 703369
Change-Id: I5b1996b131733f4792611a5f9ce14d030f1f4d1c
Reviewed-on: https://chromium-review.googlesource.com/619988
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Commit-Queue: Doug Turner <dougt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496443}
3 files changed