Merged and dist lists of unused methods from R8

Merge all the proguard_usage.zip files produced by the R8 rules and
dist the result.

Bug: 151857441
Test: m TARGET_BUILD_APPS=DocumentsUI dist
Change-Id: I7e6d73241478016093a203dc7bd86407ab86a4ac
diff --git a/core/soong_java_prebuilt.mk b/core/soong_java_prebuilt.mk
index 05f700d..5444d96 100644
--- a/core/soong_java_prebuilt.mk
+++ b/core/soong_java_prebuilt.mk
@@ -58,6 +58,14 @@
     $(intermediates.COMMON)/proguard_dictionary)
 endif
 
+ifdef LOCAL_SOONG_PROGUARD_USAGE
+  $(eval $(call copy-one-file,$(LOCAL_SOONG_PROGUARD_USAGE_ZIP),\
+    $(intermediates.COMMON)/proguard_usage.zip))
+  $(call add-dependency,$(LOCAL_BUILT_MODULE),\
+    $(intermediates.COMMON)/proguard_usage.zip)
+endif
+
+
 ifdef LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE
   my_res_package := $(intermediates.COMMON)/package-res.apk