Convert //components/proximity_auth from scoped_ptr to std::unique_ptr

components/proximity_auth/device_to_device_secure_context.cc

Index: components/proximity_auth/device_to_device_secure_context.cc
diff --git a/components/proximity_auth/device_to_device_secure_context.cc b/components/proximity_auth/device_to_device_secure_context.cc
index f8356f4c5e2a0a2ab7076b0b19cb562e7333cf55..3f0509ce4162d882a53b3f667a3a5c91dc58b597 100644
--- a/components/proximity_auth/device_to_device_secure_context.cc
+++ b/components/proximity_auth/device_to_device_secure_context.cc
@@ -27,7 +27,7 @@ const int kAuthenticationSequenceNumber = 2;
 }  // namespace
 
 DeviceToDeviceSecureContext::DeviceToDeviceSecureContext(
-    scoped_ptr<SecureMessageDelegate> secure_message_delegate,
+    std::unique_ptr<SecureMessageDelegate> secure_message_delegate,
     const std::string& symmetric_key,
     const std::string& responder_auth_message,
     ProtocolVersion protocol_version)