Replace scoped_ptr with unique_ptr in webrtc/base/

webrtc/p2p/base/dtlstransportchannel.cc

Index: webrtc/p2p/base/dtlstransportchannel.cc
diff --git a/webrtc/p2p/base/dtlstransportchannel.cc b/webrtc/p2p/base/dtlstransportchannel.cc
index 88a11928cc205aebaf5cde89a8d5d7606cc57caf..f9baa3756202de01c93ef2da9d130911971430ff 100644
--- a/webrtc/p2p/base/dtlstransportchannel.cc
+++ b/webrtc/p2p/base/dtlstransportchannel.cc
@@ -8,6 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include <memory>
 #include <utility>
 
 #include "webrtc/p2p/base/dtlstransportchannel.h"
@@ -250,7 +251,7 @@ bool DtlsTransportChannelWrapper::SetRemoteFingerprint(
   return true;
 }
 
-rtc::scoped_ptr<rtc::SSLCertificate>
+std::unique_ptr<rtc::SSLCertificate>
 DtlsTransportChannelWrapper::GetRemoteSSLCertificate() const {
   if (!dtls_) {
     return nullptr;