Add support for logtags

This lets modules declare logtags files, which will then be exported to
make using LOCAL_LOGTAGS_FILES. Make still generates event-log-tags and
the java code.

Bug: 28989759
Change-Id: Ie6be79d3ef8a17a74d42eba681a25a08b4c0e7ae
diff --git a/android/androidmk.go b/android/androidmk.go
index c8dce0f..603b37d 100644
--- a/android/androidmk.go
+++ b/android/androidmk.go
@@ -22,6 +22,7 @@
 	"os"
 	"path/filepath"
 	"sort"
+	"strings"
 
 	"android/soong"
 
@@ -200,6 +201,10 @@
 		fmt.Fprintln(w, "LOCAL_IS_HOST_MODULE := true")
 	} else {
 		fmt.Fprintln(w, "LOCAL_MODULE_TARGET_ARCH :=", archStr)
+
+		if len(amod.commonProperties.Logtags) > 0 {
+			fmt.Fprintln(w, "LOCAL_LOGTAGS_FILES := ", strings.Join(amod.commonProperties.Logtags, " "))
+		}
 	}
 
 	for _, extra := range data.Extra {