Move search to roots; Documents root; hide empty.

Documents searches now happen root-wide, instead of only under a
subdirectory.  Updates abstract class and flags to match.  Add flag
for a root to indicate it's empty, and hide empty roots in UI unless
creating.

Define "Documents" public directory and storage backend to contain
files.

Bug: 10712057, 10710865, 10710758
Change-Id: I8716367568969f9cb1d83927b2bf5a7013809350
6 files changed
tree: eccddc2a6b198be5a9cba35675e584df8c7c4d91
  1. res/
  2. src/
  3. tests/
  4. Android.mk
  5. AndroidManifest.xml