Fix source code so it compiles on google3

This is a follow up to cr/65191596 which checked for String + array warnings.

Change-Id: Id70eaa32b63b838b03be21d632c7470039b6423f
diff --git a/src/com/android/launcher3/FolderInfo.java b/src/com/android/launcher3/FolderInfo.java
index 42e2ec3..61fa7e5 100644
--- a/src/com/android/launcher3/FolderInfo.java
+++ b/src/com/android/launcher3/FolderInfo.java
@@ -19,6 +19,7 @@
 import android.content.ContentValues;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 
 /**
  * Represents a folder containing shortcuts or apps.
@@ -114,6 +115,6 @@
         return "FolderInfo(id=" + this.id + " type=" + this.itemType
                 + " container=" + this.container + " screen=" + screenId
                 + " cellX=" + cellX + " cellY=" + cellY + " spanX=" + spanX
-                + " spanY=" + spanY + " dropPos=" + dropPos + ")";
+                + " spanY=" + spanY + " dropPos=" + Arrays.toString(dropPos) + ")";
     }
 }