Cherry-pick "Send Android accessibility "content changed" event for any change"

Bug 10462111

Taken from unsubmitted https://codereview.chromium.org/23481011/ PS1
https://codereview.chromium.org/download/issue23481011_1.diff and
manually resolved.

Original change:
Send Android accessibility "content changed" event for any change.

Specifically, AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED should
be fired on the appropriate node any time the accessibility tree changes
- previously we were only firing it in a few circumstances. That
guarantees
tools like uiautomatorviewer won't see a stale accessibility tree.

BUG=286374

Change-Id: I53c337bb383dabe92625bb99d84d593f78800cf3
2 files changed