Restructure vr_ui

Get rid of pixel offset variables, and use makefile variables in
BoardConfigs.

Bug: 37779982
Test: Verified vr ui has same behavior.
Change-Id: Ifbf44e27d7101aedbe3c0e6db4b8181d56efadfd
diff --git a/Android.mk b/Android.mk
index bbb2046..95c8823 100644
--- a/Android.mk
+++ b/Android.mk
@@ -107,6 +107,12 @@
 LOCAL_CFLAGS += -DRECOVERY_UI_MARGIN_WIDTH=0
 endif
 
+ifneq ($(TARGET_RECOVERY_UI_VR_STEREO_OFFSET),)
+LOCAL_CFLAGS += -DRECOVERY_UI_VR_STEREO_OFFSET=$(TARGET_RECOVERY_UI_VR_STEREO_OFFSET)
+else
+LOCAL_CFLAGS += -DRECOVERY_UI_VR_STEREO_OFFSET=0
+endif
+
 LOCAL_C_INCLUDES += \
     system/vold \