Add bootclasspath config to its own makefile

This is part of adding some devices/products suitable for unbundled
builds. An unbundled product does not need all the PRODUCT_PACKAGES
etc present in the normal hierarchy of products, but does need to know
which jars are on the bootclasspath.

Therefore, factor out the bootclasspath config from base_system.mk and
put it in its own makefile where it can be inherited by these unbundled
products.

Bug: 172256440
Test: diff presubmit artifacts (noop)
Change-Id: Id3f91e387bba2e0525b4010f22fe380d1d8be537
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 299ebe0..1fb082b 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -327,47 +327,12 @@
     tz_version_host \
     tz_version_host_tzdata_apex \
 
-ifeq ($(ART_APEX_JARS),)
-$(error ART_APEX_JARS is empty; cannot initialize PRODUCT_BOOT_JARS variable)
-endif
-
-# The order matters for runtime class lookup performance.
-PRODUCT_BOOT_JARS := \
-    $(ART_APEX_JARS) \
-    framework-minus-apex \
-    framework-graphics \
-    ext \
-    com.android.i18n:core-icu4j \
-    telephony-common \
-    voip-common \
-    ims-common
-
-PRODUCT_UPDATABLE_BOOT_JARS := \
-    com.android.appsearch:framework-appsearch \
-    com.android.conscrypt:conscrypt \
-    com.android.media:updatable-media \
-    com.android.mediaprovider:framework-mediaprovider \
-    com.android.os.statsd:framework-statsd \
-    com.android.permission:framework-permission \
-    com.android.sdkext:framework-sdkextensions \
-    com.android.wifi:framework-wifi \
-    com.android.tethering:framework-tethering
 
 PRODUCT_COPY_FILES += \
     system/core/rootdir/init.usb.rc:system/etc/init/hw/init.usb.rc \
     system/core/rootdir/init.usb.configfs.rc:system/etc/init/hw/init.usb.configfs.rc \
     system/core/rootdir/etc/hosts:system/etc/hosts
 
-# Add the compatibility library that is needed when android.test.base
-# is removed from the bootclasspath.
-# Default to excluding android.test.base from the bootclasspath.
-ifneq ($(REMOVE_ATB_FROM_BCP),false)
-PRODUCT_PACKAGES += framework-atb-backward-compatibility
-PRODUCT_BOOT_JARS += framework-atb-backward-compatibility
-else
-PRODUCT_BOOT_JARS += android.test.base
-endif
-
 PRODUCT_COPY_FILES += system/core/rootdir/init.zygote32.rc:system/etc/init/hw/init.zygote32.rc
 PRODUCT_SYSTEM_PROPERTIES += ro.zygote?=zygote32
 
@@ -429,4 +394,5 @@
 PRODUCT_COPY_FILES += $(call add-to-product-copy-files-if-exists,\
     frameworks/base/config/dirty-image-objects:system/etc/dirty-image-objects)
 
+$(call inherit-product, $(SRC_TARGET_DIR)/product/bootclasspath.mk)
 $(call inherit-product, $(SRC_TARGET_DIR)/product/runtime_libart.mk)
diff --git a/target/product/bootclasspath.mk b/target/product/bootclasspath.mk
new file mode 100644
index 0000000..0ca6018
--- /dev/null
+++ b/target/product/bootclasspath.mk
@@ -0,0 +1,51 @@
+#
+# Copyright (C) 2020 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+ifeq ($(ART_APEX_JARS),)
+  $(error ART_APEX_JARS is empty; cannot initialize PRODUCT_BOOT_JARS variable)
+endif
+
+# The order matters for runtime class lookup performance.
+PRODUCT_BOOT_JARS := \
+    $(ART_APEX_JARS) \
+    framework-minus-apex \
+    framework-graphics \
+    ext \
+    com.android.i18n:core-icu4j \
+    telephony-common \
+    voip-common \
+    ims-common
+
+PRODUCT_UPDATABLE_BOOT_JARS := \
+    com.android.appsearch:framework-appsearch \
+    com.android.conscrypt:conscrypt \
+    com.android.media:updatable-media \
+    com.android.mediaprovider:framework-mediaprovider \
+    com.android.os.statsd:framework-statsd \
+    com.android.permission:framework-permission \
+    com.android.sdkext:framework-sdkextensions \
+    com.android.wifi:framework-wifi \
+    com.android.tethering:framework-tethering
+
+# Add the compatibility library that is needed when android.test.base
+# is removed from the bootclasspath.
+# Default to excluding android.test.base from the bootclasspath.
+ifneq ($(REMOVE_ATB_FROM_BCP),false)
+  PRODUCT_PACKAGES += framework-atb-backward-compatibility
+  PRODUCT_BOOT_JARS += framework-atb-backward-compatibility
+else
+  PRODUCT_BOOT_JARS += android.test.base
+endif