Replace scoped_ptr with unique_ptr in webrtc/base/

This propagated into various other places. Also had to #include headers that
were implicitly pulled by "scoped_ptr.h".

BUG=webrtc:5520

Review URL: https://codereview.webrtc.org/1920043002

Cr-Commit-Position: refs/heads/master@{#12501}
diff --git a/webrtc/p2p/base/transportcontroller.h b/webrtc/p2p/base/transportcontroller.h
index 9d06823..8cb5986 100644
--- a/webrtc/p2p/base/transportcontroller.h
+++ b/webrtc/p2p/base/transportcontroller.h
@@ -12,6 +12,7 @@
 #define WEBRTC_P2P_BASE_TRANSPORTCONTROLLER_H_
 
 #include <map>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -59,7 +60,7 @@
       const std::string& transport_name,
       rtc::scoped_refptr<rtc::RTCCertificate>* certificate);
   // Caller owns returned certificate
-  rtc::scoped_ptr<rtc::SSLCertificate> GetRemoteSSLCertificate(
+  std::unique_ptr<rtc::SSLCertificate> GetRemoteSSLCertificate(
       const std::string& transport_name);
   bool SetLocalTransportDescription(const std::string& transport_name,
                                     const TransportDescription& tdesc,
@@ -166,7 +167,7 @@
   bool GetLocalCertificate_w(
       const std::string& transport_name,
       rtc::scoped_refptr<rtc::RTCCertificate>* certificate);
-  rtc::scoped_ptr<rtc::SSLCertificate> GetRemoteSSLCertificate_w(
+  std::unique_ptr<rtc::SSLCertificate> GetRemoteSSLCertificate_w(
       const std::string& transport_name);
   bool SetLocalTransportDescription_w(const std::string& transport_name,
                                       const TransportDescription& tdesc,