build: Add script to generate extra images

Change-Id: I53081c7a2b4f18bc8c8a27b04d311a6b078b2022
DocumentsUI: Fix the issue of download status was displayed incompletely

The layout arrangement of date, size and summary are unreasonable.
Text was ellipsized when summary has too much characters.

Reconfigure "layout_weight" of date, size and summary can fix this
issue.

CRs-Fixed: 619201

Change-Id: I0c00d08d4793a38b80988378b4b510bdb3bf8720
Merge changes I0c00d08d,I53081c7a into android-4.4

* changes:
  DocumentsUI: Fix the issue of download status was displayed incompletely
  build: Add script to generate extra images