Set up rules to merge AndroidManifest.xmls

Now you can merge the library manifest files to the main app's
AndroidManifest.xml with LOCAL_FULL_LIBS_MANIFEST_FILES.
LOCAL_FULL_LIBS_MANIFEST_FILES is a list of paths relative to the top of
the source tree.

Bug: 12907528
Change-Id: I16a347c83dfb6fbbb7d5d40284b7c65aa682fdd2
diff --git a/core/android_manifest.mk b/core/android_manifest.mk
new file mode 100644
index 0000000..21b95c2
--- /dev/null
+++ b/core/android_manifest.mk
@@ -0,0 +1,25 @@
+# Handle AndroidManifest.xmls
+# Input: LOCAL_MANIFEST_FILE, LOCAL_FULL_MANIFEST_FILE, LOCAL_FULL_LIBS_MANIFEST_FILES
+# Output: full_android_manifest
+
+ifeq ($(strip $(LOCAL_MANIFEST_FILE)),)
+  LOCAL_MANIFEST_FILE := AndroidManifest.xml
+endif
+ifdef LOCAL_FULL_MANIFEST_FILE
+  full_android_manifest := $(LOCAL_FULL_MANIFEST_FILE)
+else
+  full_android_manifest := $(LOCAL_PATH)/$(LOCAL_MANIFEST_FILE)
+endif
+
+# Set up rules to merge library manifest files
+ifdef LOCAL_FULL_LIBS_MANIFEST_FILES
+main_android_manifest := $(full_android_manifest)
+full_android_manifest := $(intermediates.COMMON)/AndroidManifest.xml
+$(full_android_manifest): PRIVATE_LIBS_MANIFESTS := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
+$(full_android_manifest) : $(main_android_manifest) $(LOCAL_FULL_LIBS_MANIFEST_FILES)
+	@echo "Merge android manifest files: $@ <-- $^"
+	@mkdir -p $(dir $@)
+	$(hide) $(ANDROID_MANIFEST_MERGER) --main $< --libs $(PRIVATE_LIBS_MANIFESTS) \
+	    --out $@
+
+endif