Mark calls of {previous,next}PositionOf with invalid VisiblePosition deprecated

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

Index: third_party/WebKit/Source/core/editing/VisibleUnits.h
diff --git a/third_party/WebKit/Source/core/editing/VisibleUnits.h b/third_party/WebKit/Source/core/editing/VisibleUnits.h
index 881d86dab24cf56aa0e04fc3cf49fc46ef8acc87..3ad66e3b44af73a7cab808eb7a48e1444c407da2 100644
--- a/third_party/WebKit/Source/core/editing/VisibleUnits.h
+++ b/third_party/WebKit/Source/core/editing/VisibleUnits.h
@@ -138,6 +138,15 @@ CORE_EXPORT VisiblePositionInFlatTree nextPositionOf(const VisiblePositionInFlat
 CORE_EXPORT VisiblePosition previousPositionOf(const VisiblePosition&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
 CORE_EXPORT VisiblePositionInFlatTree previousPositionOf(const VisiblePositionInFlatTree&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
 
+// These deprecated functions perform synchronous layout, messing up the
+// rendering pipeline. They may also take invalid VisiblePositions as their
+// arguments. Callers should ensure clean layout and pass valid VisiblePositions
+// to the un-deprecated functions listed above.
+CORE_EXPORT VisiblePosition nextPositionOfDeprecated(const VisiblePosition&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
+CORE_EXPORT VisiblePositionInFlatTree nextPositionOfDeprecated(const VisiblePositionInFlatTree&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
+CORE_EXPORT VisiblePosition previousPositionOfDeprecated(const VisiblePosition&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
+CORE_EXPORT VisiblePositionInFlatTree previousPositionOfDeprecated(const VisiblePositionInFlatTree&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
+
 // words
 CORE_EXPORT VisiblePosition startOfWord(const VisiblePosition&, EWordSide = RightWordIfOnBoundary);
 CORE_EXPORT VisiblePositionInFlatTree startOfWord(const VisiblePositionInFlatTree&, EWordSide = RightWordIfOnBoundary);