Add OTA support to mainline_system.

update_engine applies an OTA, and update_verifier verifies
partitions post boot.

Note that this also adds cacerts_google as it's a required module by
update_engine, so this reduces the disparity between pixel /system
and mainline_system /system by ~100 files.

Bug: 110410711
Bug: 111495787
Test: make
Change-Id: Idd31407bbd5543fe1dd2b52e87894ac501a025df
diff --git a/target/product/mainline_system.mk b/target/product/mainline_system.mk
index 60a3b8d..3581c4a 100644
--- a/target/product/mainline_system.mk
+++ b/target/product/mainline_system.mk
@@ -18,6 +18,11 @@
 # device with no telephony.
 $(call inherit-product, $(SRC_TARGET_DIR)/product/handheld_system.mk)
 
+# OTA support.
+PRODUCT_PACKAGES += \
+    update_engine \
+    update_verifier \
+
 # Enable dynamic partition size
 PRODUCT_USE_DYNAMIC_PARTITION_SIZE := true