Fix X-Forwarded-* behavior in ServletUriComponentsBuilder

When using ServletUriComponentsBuilder.fromRequest, this change
makes sure that:
* the default port is used when the "X-Forwarded-Host" header is set
and no port is defined in that header value
* to use the scheme defined in the "X-Forwarded-Proto" header if set

Issue: SPR-11872

spring-webmvc/src/main/java/org/springframework/web/servlet/support/ServletUriComponentsBuilder.java

@@ -111,6 +111,7 @@ public class ServletUriComponentsBuilder extends UriComponentsBuilder {
 			}
 			else {
 				host = hostToUse;
+				port = -1;
 			}
 		}
 
@@ -119,6 +120,11 @@ public class ServletUriComponentsBuilder extends UriComponentsBuilder {
 			port = Integer.parseInt(portHeader);
 		}
 
+		String protocolHeader = request.getHeader("X-Forwarded-Proto");
+		if (StringUtils.hasText(protocolHeader)) {
+			scheme = protocolHeader;
+		}
+
 		ServletUriComponentsBuilder builder = new ServletUriComponentsBuilder();
 		builder.scheme(scheme);
 		builder.host(host);