Get rid of redundant layout tree update related to selection

third_party/WebKit/Source/core/editing/FrameSelection.h

Index: third_party/WebKit/Source/core/editing/FrameSelection.h
diff --git a/third_party/WebKit/Source/core/editing/FrameSelection.h b/third_party/WebKit/Source/core/editing/FrameSelection.h
index 6e26920c8dc7496ad381932915196860df7c2451..59b3e09441b910864ec8d56192498017293725a7 100644
--- a/third_party/WebKit/Source/core/editing/FrameSelection.h
+++ b/third_party/WebKit/Source/core/editing/FrameSelection.h
@@ -169,7 +169,7 @@ class CORE_EXPORT FrameSelection final
     return selection().getSelectionType();
   }
 
-  TextAffinity affinity() const { return selection().affinity(); }
+  TextAffinity affinity() const { return selectionInDOMTree().affinity(); }
 
   bool modify(EAlteration,
               SelectionDirection,
@@ -204,7 +204,6 @@ class CORE_EXPORT FrameSelection final
   void didChangeFocus();
 
   const SelectionInDOMTree& selectionInDOMTree() const;
-  // TODO(yosin): We should rename |isNone()| to |isVisibleNone()|.
   bool isNone() const { return selection().isNone(); }
   bool isCaret() const { return selection().isCaret(); }
   bool isRange() const { return selection().isRange(); }