Always send TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED.

Always send TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED.

This logic was borrowed from ExploreByTouchHelper, but apparently it's wrong,
because TalkBack sends ACTION_ACCESSIBILITY_FOCUS on a new view id and
then ACTION_CLEAR_ACCESSIBILITY_FOCUS on the old view id, and since we didn't
think the old view had accessibility focus, we never responded with
a TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED event, so the framework would sometimes
not update its cache, and TalkBack could think the old view still had
accessibility focus.

BUG=458343
Committed: https://crrev.com/ba0498563648b585274589f947bb57cffcdc0278
Cr-Commit-Position: refs/heads/master@{#316238}

[dmazzoni, 2015-02-12 23:37:57]

dmazzoni@chromium.org changed reviewers:
+ plundblad@chromium.org

[Peter Lundblad, 2015-02-13 17:04:34]

lgtm

[Peter Lundblad, 2015-02-13 17:05:47]

The CQ bit was checked by plundblad@chromium.org

[commit-bot: I haz the power, 2015-02-13 17:06:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/916213003/1

[commit-bot: I haz the power, 2015-02-13 17:51:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-13 17:52:35]

Patchset 1 (id:??) landed as
https://crrev.com/ba0498563648b585274589f947bb57cffcdc0278
Cr-Commit-Position: refs/heads/master@{#316238}