Less strict checked state changes and introduce disabled state for content
Sometimes, ChromeVox places range on the ancestor of a node that receives checked state changed. Ensure we cover this case when we process a checked state changed event.
Also, in order to announce disabled state uniformly, make the change to add disabled state in the renderer and make enabled state the implicit default.
BUG=
625411,
630570
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
Committed:
https://crrev.com/545a777dfe3e6410be16517f78f24602a64a55b6
Cr-Commit-Position: refs/heads/master@{#407949}