commit 472103f137c5baa7d1f7acd7330027c725c65a99
author Ben Kwa <kenobi@google.com> Wed Feb 10 15:48:25 2016 -0800
committer Ben Kwa <kenobi@google.com> Thu Feb 18 12:04:35 2016 -0800
tree 31073742e3e09de3f72f459017e11549bf090b7a
parent 9fe4e0759d93a1e87e9e31b59a64ba388ea7cdd6

Implement type-to-focus in the DirectoryFragment.

Add a helper to the FocusManager, to handle alphanumeric keystrokes.
- Build a search index mapping document titles to adapter positions, and
  keep it up-to-date.
- Intercept alphanumeric keystrokes and build up a search string from
  them.
- Use the search string and index to set focus in the directory listing.
- Highlight code is written, but not activated in the UI for now, to
  minimize surface area for potential breakages.  Revisit enabling
  highlights for O.

BUG=24988911

Change-Id: I148ff5583c655338d12bc06d6484a9ed7aa528ad