Allow for setting a logging_parent for an Apex.

Test: go test ./... -test.v -run TestOverrideApex
BUG: 148198056
Change-Id: Ib3749e59f5e31903f2dbe75f86534738147a55ec
diff --git a/apex/builder.go b/apex/builder.go
index 5e0baf4..88c7098 100644
--- a/apex/builder.go
+++ b/apex/builder.go
@@ -394,6 +394,10 @@
 		optFlags = append(optFlags, "--target_sdk_version "+targetSdkVersion)
 		optFlags = append(optFlags, "--min_sdk_version "+minSdkVersion)
 
+		if a.overridableProperties.Logging_parent != "" {
+			optFlags = append(optFlags, "--logging_parent ", a.overridableProperties.Logging_parent)
+		}
+
 		a.mergedNotices = a.buildNoticeFiles(ctx, a.Name()+suffix)
 		if a.mergedNotices.HtmlGzOutput.Valid() {
 			// If there's a NOTICE file, embed it as an asset file in the APEX.