Set ViEEncoder sink_ on construction.

webrtc/video/encoder_state_feedback_unittest.cc

Index: webrtc/video/encoder_state_feedback_unittest.cc
diff --git a/webrtc/video/encoder_state_feedback_unittest.cc b/webrtc/video/encoder_state_feedback_unittest.cc
index 7e6ec71d6eb0c5ca98addfb5636f3ff51e348432..5351e1516b18e078799630297550498b4aa30bc1 100644
--- a/webrtc/video/encoder_state_feedback_unittest.cc
+++ b/webrtc/video/encoder_state_feedback_unittest.cc
@@ -22,7 +22,7 @@ namespace webrtc {
 class MockVieEncoder : public ViEEncoder {
  public:
   explicit MockVieEncoder(ProcessThread* process_thread)
-      : ViEEncoder(1, process_thread, nullptr, nullptr) {}
+      : ViEEncoder(1, process_thread, nullptr, nullptr, nullptr) {}
   ~MockVieEncoder() {}
 
   MOCK_METHOD1(OnReceivedIntraFrameRequest, void(size_t));