Supply empty frames until codec is done with top-off.

remoting/codec/codec_test.h

Index: remoting/codec/codec_test.h
diff --git a/remoting/codec/codec_test.h b/remoting/codec/codec_test.h
index 0c143b7791e043a82e3c45bc1e4bab49d03779ef..e5d5bb63d722b1b4969aefef3e1f42e581a6508d 100644
--- a/remoting/codec/codec_test.h
+++ b/remoting/codec/codec_test.h
@@ -28,9 +28,9 @@ void TestVideoEncoder(VideoEncoder* encoder, bool strict);
 
 // Generate test data and test the encoder for a sequence of one "changed"
 // frame followed by one or more "unchanged" frames, and verify that the
-// encoder sends exactly |topoff_frames| of non-empty data for unchanged
+// encoder sends up to |max_topoff_frames| of non-empty data for unchanged
 // frames, after which it returns null frames.
-void TestVideoEncoderEmptyFrames(VideoEncoder* encoder, int topoff_frames);
+void TestVideoEncoderEmptyFrames(VideoEncoder* encoder, int max_topoff_frames);
 
 // Generate test data and test the encoder and decoder pair.
 //