Add WatchFace sample to sdk.atree

Change-Id: I24a3e34674a02c0909f5cea60ea9465f4f3395f2
diff --git a/build/sdk.atree b/build/sdk.atree
index a5fc659..c727b59 100644
--- a/build/sdk.atree
+++ b/build/sdk.atree
@@ -327,6 +327,7 @@
 developers/build/prebuilts/gradle/SpeedTracker                  samples/${PLATFORM_NAME}/wearable/SpeedTracker
 developers/build/prebuilts/gradle/SynchronizedNotifications     samples/${PLATFORM_NAME}/wearable/SynchronizedNotifications
 developers/build/prebuilts/gradle/Timer                         samples/${PLATFORM_NAME}/wearable/Timer
+developers/build/prebuilts/gradle/WatchFace                     samples/${PLATFORM_NAME}/wearable/WatchFace
 developers/build/prebuilts/gradle/WatchViewStub                 samples/${PLATFORM_NAME}/wearable/WatchViewStub
 
 # Old sample tree