Add support for ScopeDecorator and CurrentTraceContextCustomizer

See spring-projectsgh-30156

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/BraveAutoConfiguration.java

@@ -24,6 +24,8 @@
 import brave.handler.SpanHandler;
 import brave.propagation.B3Propagation;
 import brave.propagation.CurrentTraceContext;
+import brave.propagation.CurrentTraceContext.ScopeDecorator;
+import brave.propagation.CurrentTraceContextCustomizer;
 import brave.propagation.Propagation.Factory;
 import brave.propagation.ThreadLocalCurrentTraceContext;
 import brave.sampler.Sampler;
@@ -74,8 +76,16 @@ brave.Tracer braveTracer(Tracing tracing) {
 
 	@Bean
 	@ConditionalOnMissingBean
-	CurrentTraceContext currentTraceContext() {
-		return ThreadLocalCurrentTraceContext.newBuilder().build();
+	CurrentTraceContext currentTraceContext(List<CurrentTraceContext.ScopeDecorator> scopeDecorators,
+			List<CurrentTraceContextCustomizer> currentTraceContextCustomizers) {
+		ThreadLocalCurrentTraceContext.Builder builder = ThreadLocalCurrentTraceContext.newBuilder();
+		for (ScopeDecorator scopeDecorator : scopeDecorators) {
+			builder.addScopeDecorator(scopeDecorator);
+		}
+		for (CurrentTraceContextCustomizer currentTraceContextCustomizer : currentTraceContextCustomizers) {
+			currentTraceContextCustomizer.customize(builder);
+		}
+		return builder.build();
 	}
 
 	@Bean