Reinstate use of hasMappingForPattern

Use of hasMappingForPattern was commented out during work on the
Aether-based Grape implementation as it was temporarily removed in 
Spring 4's snapshots. It's since been reinstated in the snapshots, so
its use should have been reinstated prior to merging Aether work into
master.

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration.java

@@ -175,13 +175,14 @@ public class WebMvcAutoConfiguration {
 
 		@Override
 		public void addResourceHandlers(ResourceHandlerRegistry registry) {
-			// if (!registry.hasMappingForPattern("/webjars/**")) {
-			registry.addResourceHandler("/webjars/**").addResourceLocations(
-					"classpath:/META-INF/resources/webjars/");
-			// }
-			// if (!registry.hasMappingForPattern("/**")) {
-			registry.addResourceHandler("/**").addResourceLocations(RESOURCE_LOCATIONS);
-			// }
+			if (!registry.hasMappingForPattern("/webjars/**")) {
+				registry.addResourceHandler("/webjars/**").addResourceLocations(
+						"classpath:/META-INF/resources/webjars/");
+			}
+			if (!registry.hasMappingForPattern("/**")) {
+				registry.addResourceHandler("/**").addResourceLocations(
+						RESOURCE_LOCATIONS);
+			}
 		}
 
 		@Override

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/WebMvcAutoConfigurationTests.java

@@ -25,7 +25,6 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.junit.After;
-import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -57,7 +56,6 @@ import static org.junit.Assert.assertThat;
  * @author Phillip Webb
  * @author Dave Syer
  */
-@Ignore
 public class WebMvcAutoConfigurationTests {
 
 	private static final MockEmbeddedServletContainerFactory containerFactory = new MockEmbeddedServletContainerFactory();