Add java_genrule_combiner module

This module is intended to combine an implemenation generated by
java_genrule with headers from the rule's inputs.

Bug: b/285975842
Test: manual, TH
Change-Id: I9d83634ad7fa56fe5e0a6363d2891d34ac58257e
diff --git a/java/Android.bp b/java/Android.bp
index 885e682..911af83 100644
--- a/java/Android.bp
+++ b/java/Android.bp
@@ -51,6 +51,7 @@
         "gen.go",
         "generated_java_library.go",
         "genrule.go",
+        "genrule_combiner.go",
         "hiddenapi.go",
         "hiddenapi_modular.go",
         "hiddenapi_monolithic.go",
@@ -95,6 +96,7 @@
         "droiddoc_test.go",
         "droidstubs_test.go",
         "fuzz_test.go",
+        "genrule_combiner_test.go",
         "genrule_test.go",
         "generated_java_library_test.go",
         "hiddenapi_singleton_test.go",