[ThemePicker 2/N] Add an initial Theme fragment

Initial (mostly empty) implementation of ThemeFragment.
More content to come in follow-up CLs.

Bug: 120559294
Change-Id: Ic763f12cb86945b5af40e14349498660478921a4
8 files changed
tree: fd183d07bf9555d4edcf887121ee532c4eaa86c0
  1. res/
  2. src/
  3. src_override/
  4. Android.mk
  5. AndroidManifest.xml