Configure HTTP compression for HTTP/2 with Tomcat

This commit ensures that the compression options are also applied on the
`Http2Protocol` when http/2 is enabled with Tomcat.

Closes gh-15591

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/CompressionConnectorCustomizer.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -18,7 +18,9 @@ package org.springframework.boot.web.embedded.tomcat;
 
 import org.apache.catalina.connector.Connector;
 import org.apache.coyote.ProtocolHandler;
+import org.apache.coyote.UpgradeProtocol;
 import org.apache.coyote.http11.AbstractHttp11Protocol;
+import org.apache.coyote.http2.Http2Protocol;
 
 import org.springframework.boot.web.server.Compression;
 import org.springframework.util.StringUtils;
@@ -44,6 +46,24 @@ class CompressionConnectorCustomizer implements TomcatConnectorCustomizer {
 			if (handler instanceof AbstractHttp11Protocol) {
 				customize((AbstractHttp11Protocol<?>) handler);
 			}
+			for (UpgradeProtocol upgradeProtocol : connector.findUpgradeProtocols()) {
+				if (upgradeProtocol instanceof Http2Protocol) {
+					customize((Http2Protocol) upgradeProtocol);
+				}
+			}
+		}
+	}
+
+	private void customize(Http2Protocol upgradeProtocol) {
+		Compression compression = this.compression;
+		upgradeProtocol.setCompression("on");
+		upgradeProtocol.setCompressionMinSize(compression.getMinResponseSize());
+		upgradeProtocol.setCompressibleMimeType(
+				StringUtils.arrayToCommaDelimitedString(compression.getMimeTypes()));
+		if (this.compression.getExcludedUserAgents() != null) {
+			upgradeProtocol
+					.setNoCompressionUserAgents(StringUtils.arrayToCommaDelimitedString(
+							this.compression.getExcludedUserAgents()));
 		}
 	}