Fix test bug introduced in r11101.

webrtc/call/rampup_tests.cc

Index: webrtc/call/rampup_tests.cc
diff --git a/webrtc/call/rampup_tests.cc b/webrtc/call/rampup_tests.cc
index 9b31901b8a729b38a4cdefe964e3bb94ef98abb3..a3fcc302f3bdfb65b9428453e453d2bc2fd7fc00 100644
--- a/webrtc/call/rampup_tests.cc
+++ b/webrtc/call/rampup_tests.cc
@@ -87,6 +87,10 @@ test::PacketTransport* RampUpTester::CreateSendTransport(Call* sender_call) {
   return send_transport_;
 }
 
+size_t RampUpTester::GetNumVideoStreams() const {
+  return num_video_streams_;
+}
+
 void RampUpTester::ModifyVideoConfigs(
     VideoSendStream::Config* send_config,
     std::vector<VideoReceiveStream::Config>* receive_configs,