Wire up experiment for improved screenshare bwe.

webrtc/video/screenshare_loopback.cc

Index: webrtc/video/screenshare_loopback.cc
diff --git a/webrtc/video/screenshare_loopback.cc b/webrtc/video/screenshare_loopback.cc
index c0638c9b1aae0099189a6a5f72bed59919786b04..4212f35a675f7b7c4cc3120415edeeb66bf2f8ff 100644
--- a/webrtc/video/screenshare_loopback.cc
+++ b/webrtc/video/screenshare_loopback.cc
@@ -312,6 +312,7 @@ int main(int argc, char* argv[]) {
   // with a scope that outlives the test.
   std::string field_trials = webrtc::flags::FLAG_force_fieldtrials;
   webrtc::test::InitFieldTrialsFromString(field_trials);
+
   webrtc::test::RunTest(webrtc::Loopback);
   return 0;
 }