Preserve a class for testing

Addresses b/8583091

Change-Id: I89605223784312d9572dfc7c8aaa7e5eba44c4f6
diff --git a/java/src/com/android/inputmethod/research/MotionEventReader.java b/java/src/com/android/inputmethod/research/MotionEventReader.java
index e1cc2da..fbfd9b5 100644
--- a/java/src/com/android/inputmethod/research/MotionEventReader.java
+++ b/java/src/com/android/inputmethod/research/MotionEventReader.java
@@ -22,6 +22,7 @@
 import android.view.MotionEvent.PointerCoords;
 import android.view.MotionEvent.PointerProperties;
 
+import com.android.inputmethod.annotations.UsedForTesting;
 import com.android.inputmethod.latin.define.ProductionFlag;
 
 import java.io.BufferedReader;
@@ -64,6 +65,7 @@
         return replayData;
     }
 
+    @UsedForTesting
     static class ReplayData {
         final ArrayList<Integer> mActions = new ArrayList<Integer>();
         final ArrayList<PointerProperties[]> mPointerPropertiesArrays
@@ -134,6 +136,7 @@
      * },
      * </pre>
      */
+    @UsedForTesting
     /* package for test */ void readLogStatement(final JsonReader jsonReader,
             final ReplayData replayData) throws IOException {
         String logStatementType = null;