Introduce LayoutBox::paginationBreakability().

third_party/WebKit/Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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
@@ skipping 4385 matching lines @@
     // We do have overflow. We'll still be willing to paginate as long as the block
     // has auto logical height, auto or undefined max-logical-height and a zero or auto min-logical-height.
     // Note this is just a heuristic, and it's still possible to have overflow under these
     // conditions, but it should work out to be good enough for common cases. Paginating overflow
     // with scrollbars present is not the end of the world and is what we used to do in the old model anyway.
     return !style()->logicalHeight().isIntrinsicOrAuto()
         || (!style()->logicalMaxHeight().isIntrinsicOrAuto() && !style()->logicalMaxHeight().isMaxSizeNone() && (!style()->logicalMaxHeight().hasPercent() || percentageLogicalHeightIsResolvable()))
         || (!style()->logicalMinHeight().isIntrinsicOrAuto() && style()->logicalMinHeight().isPositive() && (!style()->logicalMinHeight().hasPercent() || percentageLogicalHeightIsResolvable()));
 }
 
-bool LayoutBox::isUnsplittableForPagination() const
+LayoutBox::PaginationBreakability LayoutBox::paginationBreakability() const
 {
-    return isReplaced()
+    if (isReplaced()
         || hasUnsplittableScrollingOverflow()
         || (parent() && isWritingModeRoot())
-        || (isOutOfFlowPositioned() && style()->position() == FixedPosition);
+        || (isOutOfFlowPositioned() && style()->position() == FixedPosition))
+        return ForbidBreaks;
+
+    bool checkColumnBreaks = flowThreadContainingBlock();
+    bool checkPageBreaks = !checkColumnBreaks && view()->layoutState()->pageLogicalHeight();
+    bool isUnsplittable = (checkColumnBreaks && style()->columnBreakInside() == PBAVOID)
+        || (checkPageBreaks && style()->pageBreakInside() == PBAVOID);
+    if (isUnsplittable)
+        return AvoidBreaks;
+    return AllowAnyBreaks;
 }
 
 LayoutUnit LayoutBox::lineHeight(bool /*firstLine*/, LineDirectionMode direction, LinePositionMode /*linePositionMode*/) const
 {
     if (isReplaced())
         return direction == HorizontalLine ? marginHeight() + size().height() : marginWidth() + size().width();
     return LayoutUnit();
 }
 
 int LayoutBox::baselinePosition(FontBaseline baselineType, bool /*firstLine*/, LineDirectionMode direction, LinePositionMode linePositionMode) const
@@ skipping 414 matching lines @@
     StyleImage* borderImage = style()->borderImage().image();
     return borderImage && borderImage->canRender(*this, style()->effectiveZoom()) && borderImage->isLoaded();
 }
 
 ShapeOutsideInfo* LayoutBox::shapeOutsideInfo() const
 {
     return ShapeOutsideInfo::isEnabledFor(*this) ? ShapeOutsideInfo::info(*this) : nullptr;
 }
 
 } // namespace blink