"up-to-date" should only use hyphens when used as compound modifier of a noun

pdf/paint_aggregator.h

Index: pdf/paint_aggregator.h
diff --git a/pdf/paint_aggregator.h b/pdf/paint_aggregator.h
index 96f61e087875f387bfe3f3daba76dda6f7e05fc0..74737ab8fb66b6b3165fa46fbb614bb30afcd522 100644
--- a/pdf/paint_aggregator.h
+++ b/pdf/paint_aggregator.h
@@ -90,7 +90,7 @@ class PaintAggregator {
   //    InvalidateRect. We need to know this distinction for some operations.
   //
   //  - The paint bounds union is computed on the fly so we don't have to keep
-  //    a rectangle up-to-date as we do different operations.
+  //    a rectangle up to date as we do different operations.
   class InternalPaintUpdate {
    public:
     InternalPaintUpdate();