0cd996b5be
Rename AXObject to AXObjectImpl in modules/ and web/, and introduce an
empty abstract parent class in core/. This is pre-work to remove usages
of AXObjectImpl from web/, which will use AXObject instead.
This patch does not rename the usages in core/ since these should use
the new abstract object.
BUG=715382
Review-Url: https://codereview.chromium.org/2858493002
Cr-Original-Commit-Position: refs/heads/master@{#471663}
Committed: 234813ae8d
Review-Url: https://codereview.chromium.org/2858493002
Cr-Commit-Position: refs/heads/master@{#472370}