Migrate removeSelection from BrowserAccessiblity to AXPlatformNode

Bug: 703369
Change-Id: Ifab324cf226c59881214be0d2d7c5c22ba1d0066
Reviewed-on: https://chromium-review.googlesource.com/659257
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501481}
5 files changed