Add VisitDirectDepsWithTag

Add a method on ModuleContext and TopDownMutatorContext to visit
direct dependencies that have a given dependency tag.

Test: m checkbuild
Change-Id: Ib875563091dcae6b7282b3e3427d0eb07d8c8af5
diff --git a/java/system_modules.go b/java/system_modules.go
index 5234d17..196d041 100644
--- a/java/system_modules.go
+++ b/java/system_modules.go
@@ -112,11 +112,9 @@
 func (system *SystemModules) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	var jars android.Paths
 
-	ctx.VisitDirectDeps(func(module android.Module) {
-		if ctx.OtherModuleDependencyTag(module) == libTag {
-			dep, _ := module.(Dependency)
-			jars = append(jars, dep.HeaderJars()...)
-		}
+	ctx.VisitDirectDepsWithTag(libTag, func(module android.Module) {
+		dep, _ := module.(Dependency)
+		jars = append(jars, dep.HeaderJars()...)
 	})
 
 	jars = append(jars, android.PathsForModuleSrc(ctx, system.properties.Jars)...)