Make a method in ProtoOutputFormatter visible for tests.

--
MOS_MIGRATED_REVID=135495077
diff --git a/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java b/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java
index 3852ce2..2c9d00d 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/output/ProtoOutputFormatter.java
@@ -19,6 +19,7 @@
 import static com.google.devtools.build.lib.query2.proto.proto2api.Build.Target.Discriminator.RULE;
 import static com.google.devtools.build.lib.query2.proto.proto2api.Build.Target.Discriminator.SOURCE_FILE;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMultimap;
 import com.google.common.collect.Iterables;
@@ -131,10 +132,9 @@
     return options.orderOutput == OrderOutput.FULL ? getSortedLabels(result) : result.getLabels();
   }
 
-  /**
-   * Converts a logical {@link Target} object into a {@link Build.Target} protobuffer.
-   */
-  protected Build.Target toTargetProtoBuffer(Target target) throws InterruptedException {
+  /** Converts a logical {@link Target} object into a {@link Build.Target} protobuffer. */
+  @VisibleForTesting
+  public Build.Target toTargetProtoBuffer(Target target) throws InterruptedException {
     Build.Target.Builder targetPb = Build.Target.newBuilder();
 
     String location = getLocation(target, relativeLocations);