Don't create ApplicationContextHeaderFilter when header is disabled

See gh-4320
Closes gh-4454

Author: eddumelendez

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcAutoConfiguration.java

@@ -42,6 +42,7 @@
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration;
@@ -87,6 +88,7 @@
  * @author Christian Dupuis
  * @author Andy Wilkinson
  * @author Johannes Edmeier
+ * @author Eddú Meléndez
  */
 @Configuration
 @ConditionalOnClass({ Servlet.class, DispatcherServlet.class })
@@ -198,6 +200,7 @@ public Object getProperty(String name) {
 	// Put Servlets and Filters in their own nested class so they don't force early
 	// instantiation of ManagementServerProperties.
 	@Configuration
+	@ConditionalOnProperty(prefix = "management", name = "addApplicationContextHeader", matchIfMissing = true, havingValue = "true")
 	protected static class ApplicationContextFilterConfiguration {
 
 		@Bean

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcAutoConfigurationTests.java

@@ -98,6 +98,7 @@
  * @author Phillip Webb
  * @author Greg Turnquist
  * @author Andy Wilkinson
+ * @author Eddú Meléndez
  */
 public class EndpointWebMvcAutoConfigurationTests {
 
@@ -136,6 +137,7 @@ public void onSamePort() throws Exception {
 		assertContent("/controller", ports.get().management, null);
 		assertContent("/endpoint", ports.get().management, null);
 		assertTrue(hasHeader("/endpoint", ports.get().server, "X-Application-Context"));
+		assertTrue(this.applicationContext.containsBean("applicationContextIdFilter"));
 		this.applicationContext.close();
 		assertAllClosed();
 	}
@@ -149,6 +151,7 @@ public void onSamePortWithoutHeader() throws Exception {
 				EndpointWebMvcAutoConfiguration.class);
 		this.applicationContext.refresh();
 		assertFalse(hasHeader("/endpoint", ports.get().server, "X-Application-Context"));
+		assertFalse(this.applicationContext.containsBean("applicationContextIdFilter"));
 		this.applicationContext.close();
 		assertAllClosed();
 	}