Replace scoped_ptr with unique_ptr in webrtc/modules/video_coding/

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1721353002

Cr-Commit-Position: refs/heads/master@{#11814}
diff --git a/webrtc/modules/video_coding/jitter_buffer.cc b/webrtc/modules/video_coding/jitter_buffer.cc
index 663bf03..ca8c0d9 100644
--- a/webrtc/modules/video_coding/jitter_buffer.cc
+++ b/webrtc/modules/video_coding/jitter_buffer.cc
@@ -215,7 +215,7 @@
 }
 
 VCMJitterBuffer::VCMJitterBuffer(Clock* clock,
-                                 rtc::scoped_ptr<EventWrapper> event)
+                                 std::unique_ptr<EventWrapper> event)
     : clock_(clock),
       running_(false),
       crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),