Add VideoEncoder.ScalingSettings.toString method.

Bug: None
Change-Id: Ib7563bdec49736b104d3cbb52a7c77b6aa142030
Reviewed-on: https://webrtc-review.googlesource.com/70500
Reviewed-by: Paulina Hensman <phensman@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22922}
diff --git a/BUILD.gn b/BUILD.gn
index 25a2fb4..8eab817 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -576,6 +576,7 @@
         "examples/androidjunit/src/org/appspot/apprtc/DirectRTCClientTest.java",
         "examples/androidjunit/src/org/appspot/apprtc/TCPChannelClientTest.java",
         "sdk/android/tests/src/org/webrtc/CameraEnumerationTest.java",
+        "sdk/android/tests/src/org/webrtc/ScalingSettingsTest.java",
       ]
 
       deps = [