UI Widgets documentation for Wear 2.0 preview. am: 0fce5d1328 am: cf3fa15b3e
am: c87446f5a8

* commit 'c87446f5a8c75598bcc79e9400eaaf4839e105c4':
  UI Widgets documentation for Wear 2.0 preview.

Change-Id: I2798b6433215aaf6ee983f8b75ff2f3cd1dc6054