Cast: Synthetic benchmark tool.

media/cast/video_sender/fake_software_video_encoder.cc

Index: media/cast/video_sender/fake_software_video_encoder.cc
diff --git a/media/cast/video_sender/fake_software_video_encoder.cc b/media/cast/video_sender/fake_software_video_encoder.cc
index ee8fe0fd00c52e445570808f5a21c186c08a640b..7c5c95264193fd02939eabad8906215521c9e339 100644
--- a/media/cast/video_sender/fake_software_video_encoder.cc
+++ b/media/cast/video_sender/fake_software_video_encoder.cc
@@ -45,8 +45,9 @@ bool FakeSoftwareVideoEncoder::Encode(
   values.SetInteger("ref", encoded_image->referenced_frame_id);
   values.SetInteger("id", encoded_image->frame_id);
   values.SetInteger("size", frame_size_);
-  values.SetString("data", std::string(frame_size_, ' '));
   base::JSONWriter::Write(&values, &encoded_image->data);
+  encoded_image->data.resize(
+      std::max<size_t>(encoded_image->data.size(), frame_size_));
   return true;
 }