fixed indentation

AsyncDisplayKit/ASButtonNode.mm

@@ -390,26 +390,26 @@
 
 - (UIImage *)backgroundImageForState:(ASControlState)state
 {
-    ASDN::MutexLocker l(_propertyLock);
+  ASDN::MutexLocker l(_propertyLock);
-    switch (state) {
+  switch (state) {
-      case ASControlStateNormal:
+    case ASControlStateNormal:
-        return _normalBackgroundImage;
+      return _normalBackgroundImage;
-            
+    
-      case ASControlStateHighlighted:
+    case ASControlStateHighlighted:
-        return _highlightedBackgroundImage;
+      return _highlightedBackgroundImage;
-            
+    
-      case ASControlStateSelected:
+    case ASControlStateSelected:
-        return _selectedBackgroundImage;
+      return _selectedBackgroundImage;
-            
+    
-      case ASControlStateSelected | ASControlStateHighlighted:
+    case ASControlStateSelected | ASControlStateHighlighted:
-        return _selectedHighlightedBackgroundImage;
+      return _selectedHighlightedBackgroundImage;
-      
+    
-      case ASControlStateDisabled:
+    case ASControlStateDisabled:
-        return _disabledBackgroundImage;
+      return _disabledBackgroundImage;
-            
+    
-      default:
+    default:
-        return _normalBackgroundImage;
+      return _normalBackgroundImage;
-    }
+  }
 }
 
 - (void)setBackgroundImage:(UIImage *)image forState:(ASControlState)state