Replace the remaining scoped_ptr with unique_ptr in webrtc/modules/

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1921233002

Cr-Commit-Position: refs/heads/master@{#12511}
diff --git a/webrtc/modules/video_coding/jitter_buffer_unittest.cc b/webrtc/modules/video_coding/jitter_buffer_unittest.cc
index df70ea9..eb7d78b 100644
--- a/webrtc/modules/video_coding/jitter_buffer_unittest.cc
+++ b/webrtc/modules/video_coding/jitter_buffer_unittest.cc
@@ -195,7 +195,7 @@
   MOCK_METHOD1(WakeUp, void(Module* module));
   MOCK_METHOD1(RegisterModule, void(Module* module));
   MOCK_METHOD1(DeRegisterModule, void(Module* module));
-  void PostTask(rtc::scoped_ptr<ProcessTask> task) {}
+  void PostTask(std::unique_ptr<ProcessTask> task) {}
 };
 
 class TestBasicJitterBuffer : public ::testing::TestWithParam<std::string>,