Fix android accessibility action handling to return true on success and to fail on stale nodes.
This fixes clicking on nodes in the accessibility node tree using
BrailleBack. Before, BrailleBack would emit its not by everyone
appreciated failure beep when clicking, leading the user to think
that the click didn't work. Now, we return true for successful actions
and also send the appropriate VIEW_CLICKED event for a click action.
Also, stop performing actions (such as setting focus) to nodes that aren't
in the tree.
BUG=none
R=dmazzoni@chomium.org
Review URL: https://codereview.chromium.org/
110063004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240313 0039d316-1c4b-4281-b951-d872f2087c98