DocumentsUI: Add new private intent action to select copy destination.

The CL adds INTENT_ACTION_OPEN_COPY_DESTINATION, and implements the behavior to
respond the intent action.

The directory picker:
 * filter out read only roots
 * return document URI instead of document tree URI
for the intent action.

BUG=b:20146034
Change-Id: I96c565100c3cdaa57cc7abd8cf6d895d148941a7
4 files changed
tree: 480b33e8b7bb6621ffa089244f785fbaf1be013d
  1. res/
  2. src/
  3. tests/
  4. Android.mk
  5. AndroidManifest.xml
  6. wrap_alpha.py