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

android/androidmk.go

@@ -22,6 +22,7 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strings"
 
 	"android/soong"
 
@@ -200,6 +201,10 @@ func translateAndroidMkModule(ctx blueprint.SingletonContext, w io.Writer, mod b
 		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 {

android/module.go

@@ -111,6 +111,10 @@ type commonProperties struct {
 	// whether this is a proprietary vendor module, and should be installed into /vendor
 	Proprietary bool
 
+	// *.logtags files, to combine together in order to generate the /system/etc/event-log-tags
+	// file
+	Logtags []string
+
 	// Set by HostOrDeviceMutator
 	CompileHostOrDevice HostOrDevice `blueprint:"mutated"`