Collect NOTICE files for apps_only build.

In apps_only build (after running tapas or exporting TARGET_BUILD_APPS),
run "make notice_files" to collect and combine the NOTICE files of
modules that are needed by the apps.

Bug: 10445634
Change-Id: I6555bba1104e43b48c723c82143c46d444a75e80
diff --git a/core/main.mk b/core/main.mk
index b8a8191..0b43efe 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -836,6 +836,15 @@
 
 droid: apps_only
 
+# Combine the NOTICE files for a apps_only build
+$(eval $(call combine-notice-files, \
+    $(target_notice_file_txt), \
+    $(target_notice_file_html), \
+    "Notices for files for apps:", \
+    $(TARGET_OUT_NOTICE_FILES), \
+    $(apps_only_installed_files)))
+
+
 else # TARGET_BUILD_APPS
   $(call dist-for-goals, droidcore, \
     $(INTERNAL_UPDATE_PACKAGE_TARGET) \