Annotate libjingle_peerconnection_java with @Nullable.

Bug: webrtc:8881
Change-Id: Ida2ef6c003567d19529c21629c916ed40e8de3a6
Reviewed-on: https://webrtc-review.googlesource.com/63380
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Paulina Hensman <phensman@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22563}
diff --git a/sdk/android/api/org/webrtc/VideoEncoder.java b/sdk/android/api/org/webrtc/VideoEncoder.java
index f4836c9..af656bb 100644
--- a/sdk/android/api/org/webrtc/VideoEncoder.java
+++ b/sdk/android/api/org/webrtc/VideoEncoder.java
@@ -10,6 +10,7 @@
 
 package org.webrtc;
 
+import javax.annotation.Nullable;
 import org.webrtc.EncodedImage;
 
 /**
@@ -93,8 +94,8 @@
   /** Settings for WebRTC quality based scaling. */
   public class ScalingSettings {
     public final boolean on;
-    public final Integer low;
-    public final Integer high;
+    @Nullable public final Integer low;
+    @Nullable public final Integer high;
 
     /**
      * Settings to disable quality based scaling.