Clean up PageBoundaryRule enum.

Source/core/layout/LayoutBlock.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 350 matching lines @@
     void markLinesDirtyInBlockRange(LayoutUnit logicalTop, LayoutUnit logicalBottom, RootInlineBox* highest = nullptr);
 
     Position positionForBox(InlineBox*, bool start = true) const;
     PositionWithAffinity positionForPointWithInlineChildren(const LayoutPoint&);
 
     // End helper functions and structs used by layoutBlockChildren.
 
     void removeFromGlobalMaps();
     bool widthAvailableToChildrenHasChanged();
 
+public:
+    // Specify which page or column to associate with an offset, if said offset is exactly at a page
+    // or column boundary.
+    enum PageBoundaryRule { AssociateWithFormerPage, AssociateWithLatterPage };
+
+    LayoutUnit pageLogicalHeightForOffset(LayoutUnit) const;
+    LayoutUnit pageRemainingLogicalHeightForOffset(LayoutUnit, PageBoundaryRule) const;
+
 protected:
     bool isPageLogicalHeightKnown(LayoutUnit logicalOffset) const { return pageLogicalHeightForOffset(logicalOffset); }
 
-    // Returns the logicalOffset at the top of the next page. If the offset passed in is already at the top of the current page,
-    // then nextPageLogicalTop with ExcludePageBoundary will still move to the top of the next page. nextPageLogicalTop with
-    // IncludePageBoundary set will not.
+    // Returns the logical offset at the top of the next page, for a given offset.
     //
-    // For a page height of 800px, the first rule will return 800 if the value passed in is 0. The second rule will simply return 0.
-    enum PageBoundaryRule { ExcludePageBoundary, IncludePageBoundary };
-    LayoutUnit nextPageLogicalTop(LayoutUnit logicalOffset, PageBoundaryRule = ExcludePageBoundary) const;
+    // If the given offset is at a page boundary, using AssociateWithLatterPage as PageBoundaryRule
+    // will move us one page ahead (since the offset is at the top of the "current" page). Using
+    // AssociateWithFormerPage instead will keep us where we are (since the offset is at the bottom
+    // of the "current" page, which is exactly the same offset as the top offset on the next page).
+    //
+    // For a page height of 800px, AssociateWithLatterPage will return 1600 if the value passed in
+    // is 800. AssociateWithFormerPage will simply return 800.
+    LayoutUnit nextPageLogicalTop(LayoutUnit logicalOffset, PageBoundaryRule) const;
 
     bool createsNewFormattingContext() const;
 
-public:
-    LayoutUnit pageLogicalHeightForOffset(LayoutUnit offset) const;
-    LayoutUnit pageRemainingLogicalHeightForOffset(LayoutUnit offset, PageBoundaryRule = IncludePageBoundary) const;
-
-protected:
     // A page break is required at some offset due to space shortage in the current fragmentainer.
     void setPageBreak(LayoutUnit offset, LayoutUnit spaceShortage);
 
     // Update minimum page height required to avoid fragmentation where it shouldn't occur (inside
     // unbreakable content, between orphans and widows, etc.). This will be used as a hint to the
     // column balancer to help set a good minimum column height.
     void updateMinimumPageHeight(LayoutUnit offset, LayoutUnit minHeight);
 
     // Adjust from painting offsets to the local coords of this layoutObject
     void offsetForContents(LayoutPoint&) const;
@@ skipping 22 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of LayoutBlock and into LayoutBlockFlow.
     friend class LayoutBlockFlow;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlock, isLayoutBlock());
 
 } // namespace blink
 
 #endif // LayoutBlock_h