Rename AXPlatformPosition to BrowserAccessibilityPosition.

The AXPlatformPosition class really is specific to how BrowserAccessibility
works and thus we should rename it as such.  We will be adding a new
AXPlatformPosition that depends on AXPlatformNode and at some point convert
all usages to it.

Bug: 703369
Change-Id: Icf8882be7d92b91a017dcf90ee8ca31716d7eabe
Reviewed-on: https://chromium-review.googlesource.com/698870
Commit-Queue: Doug Turner <dougt@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512373}
10 files changed