Merge changes Icf44032f,Iec8524d3

* changes:
  Add the missing dependency on BOARD_PREBUILT_DTBOIMAGE.
  use BOARD_PREBUILT_DTBOIMAGE in target-files-package
diff --git a/core/Makefile b/core/Makefile
index cc5a6e0..f11e3a6 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -2811,19 +2811,20 @@
 ifdef BOARD_SUPER_PARTITION_SIZE
 
 INSTALLED_SUPERIMAGE_TARGET := $(PRODUCT_OUT)/super.img
+INSTALLED_SUPERIMAGE_EMPTY_TARGET := $(PRODUCT_OUT)/super_empty.img
+
 $(INSTALLED_SUPERIMAGE_TARGET): $(call images-for-partitions,$(BOARD_SUPER_PARTITION_PARTITION_LIST))
 
 # For A/B devices, super partition always contains sub-partitions in the _a slot, because this
 # image should only be used for bootstrapping / initializing the device. When flashing the image,
 # bootloader fastboot should always mark _a slot as bootable.
 ifeq ($(AB_OTA_UPDATER),true)
-$(INSTALLED_SUPERIMAGE_TARGET): PRIVATE_PARTITION_SUFFIX=_a
-$(INSTALLED_SUPERIMAGE_TARGET): PRIVATE_METADATA_SLOTS=2
+$(INSTALLED_SUPERIMAGE_TARGET) $(INSTALLED_SUPERIMAGE_EMPTY_TARGET): PRIVATE_PARTITION_SUFFIX=_a
+$(INSTALLED_SUPERIMAGE_TARGET) $(INSTALLED_SUPERIMAGE_EMPTY_TARGET): PRIVATE_METADATA_SLOTS=2
 else
-$(INSTALLED_SUPERIMAGE_TARGET): PRIVATE_METADATA_SLOTS=1
+$(INSTALLED_SUPERIMAGE_TARGET) $(INSTALLED_SUPERIMAGE_EMPTY_TARGET): PRIVATE_METADATA_SLOTS=1
 endif # AB_OTA_UPDATER
 
-
 $(INSTALLED_SUPERIMAGE_TARGET): $(HOST_OUT_EXECUTABLES)/lpmake
 	$< \
 		--sparse \
@@ -2837,6 +2838,17 @@
 
 $(call dist-for-goals,dist_files,$(INSTALLED_SUPERIMAGE_TARGET))
 
+$(INSTALLED_SUPERIMAGE_EMPTY_TARGET): $(HOST_OUT_EXECUTABLES)/lpmake
+	$< \
+		--metadata-size 65536 \
+		--metadata-slots $(PRIVATE_METADATA_SLOTS) \
+		--device-size $(BOARD_SUPER_PARTITION_SIZE) \
+		--output $@ \
+		$(foreach name,$(BOARD_SUPER_PARTITION_PARTITION_LIST), \
+			--partition $(name)$(PRIVATE_PARTITION_SUFFIX):$$($(UUIDGEN) $(name)$(PRIVATE_SUPER_PARTITION_SUFFIX)):readonly:0)
+
+$(call dist-for-goals,dist_files,$(INSTALLED_SUPERIMAGE_EMPTY_TARGET))
+
 endif # BOARD_SUPER_PARTITION_SIZE
 endif # PRODUCT_BUILD_SUPER_PARTITION
 
diff --git a/core/main.mk b/core/main.mk
index c5067b1..25887d0 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1211,6 +1211,9 @@
 .PHONY: superimage
 superimage: $(INSTALLED_SUPERIMAGE_TARGET)
 
+.PHONY: superimage_empty
+superimage_empty: $(INSTALLED_SUPERIMAGE_EMPTY_TARGET)
+
 .PHONY: bootimage
 bootimage: $(INSTALLED_BOOTIMAGE_TARGET)
 
@@ -1233,6 +1236,7 @@
     $(INSTALLED_BPTIMAGE_TARGET) \
     $(INSTALLED_VENDORIMAGE_TARGET) \
     $(INSTALLED_ODMIMAGE_TARGET) \
+    $(INSTALLED_SUPERIMAGE_EMPTY_TARGET) \
     $(INSTALLED_PRODUCTIMAGE_TARGET) \
     $(INSTALLED_SYSTEMOTHERIMAGE_TARGET) \
     $(INSTALLED_FILES_FILE) \
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