Make room for any scrollbars in the content box and border box.

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
@@ skipping 966 matching lines @@
   return GetScrollableArea()->VerticalScrollbarWidth();
 }
 
 int LayoutBox::HorizontalScrollbarHeight() const {
   if (!HasOverflowClip() || Style()->OverflowX() == EOverflow::kOverlay)
     return 0;
 
   return GetScrollableArea()->HorizontalScrollbarHeight();
 }
 
-LayoutUnit LayoutBox::VerticalScrollbarWidthClampedToContentBox() const {
-  LayoutUnit width(VerticalScrollbarWidth());
-  DCHECK_GE(width, LayoutUnit());
-  if (width) {
-    LayoutUnit minimum_width = LogicalWidth() - BorderAndPaddingLogicalWidth();
-    DCHECK_GE(minimum_width, LayoutUnit());
-    width = std::min(width, minimum_width);
-  }
-  return width;
-}
-
 ScrollResult LayoutBox::Scroll(ScrollGranularity granularity,
                                const FloatSize& delta) {
   // Presumably the same issue as in setScrollTop. See crbug.com/343132.
   DisableCompositingQueryAsserts disabler;
 
   if (!GetScrollableArea())
     return ScrollResult();
 
   return GetScrollableArea()->UserScroll(granularity, delta);
 }
@@ skipping 455 matching lines @@
 void LayoutBox::ClearOverrideContainingBlockContentLogicalHeight() {
   if (!rare_data_)
     return;
   EnsureRareData().has_override_containing_block_content_logical_height_ =
       false;
 }
 
 LayoutUnit LayoutBox::AdjustBorderBoxLogicalWidthForBoxSizing(
     float width) const {
   LayoutUnit borders_plus_padding = CollapsedBorderAndCSSPaddingLogicalWidth();
+  LayoutUnit scrollbar_size(VerticalScrollbarWidth());
   LayoutUnit result(width);
   if (Style()->BoxSizing() == EBoxSizing::kContentBox)
-    return result + borders_plus_padding;
-  return std::max(result, borders_plus_padding);
+    return std::max(result, scrollbar_size) + borders_plus_padding;
+  return std::max(result, borders_plus_padding + scrollbar_size);
 }
 
 LayoutUnit LayoutBox::AdjustBorderBoxLogicalHeightForBoxSizing(
     float height) const {
   LayoutUnit borders_plus_padding = CollapsedBorderAndCSSPaddingLogicalHeight();
+  LayoutUnit scrollbar_size(HorizontalScrollbarHeight());
   LayoutUnit result(height);
   if (Style()->BoxSizing() == EBoxSizing::kContentBox)
-    return result + borders_plus_padding;
-  return std::max(result, borders_plus_padding);
+    return std::max(result, scrollbar_size) + borders_plus_padding;
+  return std::max(result, borders_plus_padding + scrollbar_size);
 }
 
 LayoutUnit LayoutBox::AdjustContentBoxLogicalWidthForBoxSizing(
     float width) const {
   LayoutUnit result(width);
   if (Style()->BoxSizing() == EBoxSizing::kBorderBox)
     result -= CollapsedBorderAndCSSPaddingLogicalWidth();
-  return std::max(LayoutUnit(), result);
+  return std::max(LayoutUnit(VerticalScrollbarWidth()), result);
 }
 
 LayoutUnit LayoutBox::AdjustContentBoxLogicalHeightForBoxSizing(
     float height) const {
   LayoutUnit result(height);
   if (Style()->BoxSizing() == EBoxSizing::kBorderBox)
     result -= CollapsedBorderAndCSSPaddingLogicalHeight();
-  return std::max(LayoutUnit(), result);
+  return std::max(LayoutUnit(HorizontalScrollbarHeight()), result);
 }
 
 // Hit Testing
 bool LayoutBox::NodeAtPoint(HitTestResult& result,
                             const HitTestLocation& location_in_container,
                             const LayoutPoint& accumulated_offset,
                             HitTestAction action) {
   LayoutPoint adjusted_location = accumulated_offset + Location();
 
   if (!RootScrollerUtil::IsEffective(*this)) {
@@ skipping 4386 matching lines @@
 void LayoutBox::MutableForPainting::
     SavePreviousContentBoxSizeAndLayoutOverflowRect() {
   auto& rare_data = GetLayoutBox().EnsureRareData();
   rare_data.has_previous_content_box_size_and_layout_overflow_rect_ = true;
   rare_data.previous_content_box_size_ = GetLayoutBox().ContentBoxRect().Size();
   rare_data.previous_layout_overflow_rect_ =
       GetLayoutBox().LayoutOverflowRect();
 }
 
 }  // namespace blink