Automatically fire AX events on Mac based on tree changes
This change uses tree changes to automatically determine
which Mac AX events to fire, rather than getting the events
directly from Blink. The code to fire events from Blink is
removed for OS_MACOSX in this change.
Subsequent changes will do the same for Windows, Linux,
Android, and Chrome OS, and then we can delete all of the
code that fires specific events from Blink, and just mark
AX nodes as dirty instead.
BUG=699438
Review-Url: https://codereview.chromium.org/2917363002
Cr-Commit-Position: refs/heads/master@{#477889}
20 files changed
