Prototype changes for multitree

This change contains a prototype implementation for multitree.
A new file core/tasks/multitree.mk adds a goal named "update-meta",
which searches for "imported" and "exported" Android.bp modules and
writes a json metadata to track dependencies between components.

Bug: 230448564
Test: m
Change-Id: Ie93e3bf130cacb6b6de41acee3bd302f64f1ab95

core/soong_config.mk

@@ -169,6 +169,8 @@ $(call add_json_list, RecoverySnapshotDirsIncluded,      $(RECOVERY_SNAPSHOT_DIR
 $(call add_json_list, RecoverySnapshotDirsExcluded,      $(RECOVERY_SNAPSHOT_DIRS_EXCLUDED))
 $(call add_json_bool, HostFakeSnapshotEnabled,           $(HOST_FAKE_SNAPSHOT_ENABLE))
 
+$(call add_json_bool, MultitreeUpdateMeta,               $(filter true,$(TARGET_MULTITREE_UPDATE_META)))
+
 $(call add_json_bool, Treble_linker_namespaces,          $(filter true,$(PRODUCT_TREBLE_LINKER_NAMESPACES)))
 $(call add_json_bool, Enforce_vintf_manifest,            $(filter true,$(PRODUCT_ENFORCE_VINTF_MANIFEST)))
 

core/tasks/multitree.mk

@@ -0,0 +1,16 @@
+# Copyright (C) 2022 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.
+
+.PHONY: update-meta
+update-meta: $(SOONG_MULTITREE_METADATA)