Export the cert path for runtime_resource_overlay.

Fixes: 119811120
Test: app_test.go
Test: Converted and built IconPackFilledSystemUIOverlay
Change-Id: I3f7eae3127996773c5abf9f9bdb9d57a198ddaa3
diff --git a/java/androidmk.go b/java/androidmk.go
index 6d4d40b..d76e29b 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -341,7 +341,7 @@
 
 				entries.SetBoolIfTrue("LOCAL_PRIVILEGED_MODULE", app.Privileged())
 
-				entries.SetPath("LOCAL_CERTIFICATE", app.certificate.Pem)
+				entries.SetString("LOCAL_CERTIFICATE", app.certificate.AndroidMkString())
 				entries.AddStrings("LOCAL_OVERRIDES_PACKAGES", app.getOverriddenPackages()...)
 
 				for _, jniLib := range app.installJniLibs {
@@ -699,6 +699,7 @@
 		Include:    "$(BUILD_SYSTEM)/soong_app_prebuilt.mk",
 		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
 			func(entries *android.AndroidMkEntries) {
+				entries.SetString("LOCAL_CERTIFICATE", r.certificate.AndroidMkString())
 				entries.SetPath("LOCAL_MODULE_PATH", r.installDir.ToMakePath())
 			},
 		},