Remove statusCode state tracking

Closes gh-23490

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/filter/ShallowEtagHeaderFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -112,7 +112,7 @@ private void updateResponse(HttpServletRequest request, HttpServletResponse resp
 				WebUtils.getNativeResponse(response, ContentCachingResponseWrapper.class);
 		Assert.notNull(responseWrapper, "ContentCachingResponseWrapper not found");
 		HttpServletResponse rawResponse = (HttpServletResponse) responseWrapper.getResponse();
-		int statusCode = responseWrapper.getStatusCode();
+		int statusCode = responseWrapper.getStatus();
 
 		if (rawResponse.isCommitted()) {
 			responseWrapper.copyBodyToResponse();

spring-web/src/main/java/org/springframework/web/util/ContentCachingResponseWrapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,8 +51,6 @@ public class ContentCachingResponseWrapper extends HttpServletResponseWrapper {
 	@Nullable
 	private PrintWriter writer;
 
-	private int statusCode = HttpServletResponse.SC_OK;
-
 	@Nullable
 	private Integer contentLength;
 
@@ -66,19 +64,6 @@ public ContentCachingResponseWrapper(HttpServletResponse response) {
 	}
 
 
-	@Override
-	public void setStatus(int sc) {
-		super.setStatus(sc);
-		this.statusCode = sc;
-	}
-
-	@SuppressWarnings("deprecation")
-	@Override
-	public void setStatus(int sc, String sm) {
-		super.setStatus(sc, sm);
-		this.statusCode = sc;
-	}
-
 	@Override
 	public void sendError(int sc) throws IOException {
 		copyBodyToResponse(false);
@@ -89,7 +74,6 @@ public void sendError(int sc) throws IOException {
 			// Possibly on Tomcat when called too late: fall back to silent setStatus
 			super.setStatus(sc);
 		}
-		this.statusCode = sc;
 	}
 
 	@Override
@@ -103,7 +87,6 @@ public void sendError(int sc, String msg) throws IOException {
 			// Possibly on Tomcat when called too late: fall back to silent setStatus
 			super.setStatus(sc, msg);
 		}
-		this.statusCode = sc;
 	}
 
 	@Override
@@ -176,9 +159,11 @@ public void reset() {
 
 	/**
 	 * Return the status code as specified on the response.
+	 * @deprecated as of 5.2 in favor of {@link HttpServletResponse#getStatus()}
 	 */
+	@Deprecated
 	public int getStatusCode() {
-		return this.statusCode;
+		return getStatus();
 	}
 
 	/**