Transition to explicit constructors in LayoutUnit

third_party/WebKit/Source/core/layout/LayoutBlockFlow.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) 2003-2013 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ skipping 81 matching lines @@
     static LayoutBlockFlow* createAnonymous(Document*);
 
     bool isLayoutBlockFlow() const final { return true; }
 
     void layoutBlock(bool relayoutChildren) override;
 
     void computeOverflow(LayoutUnit oldClientAfterEdge, bool recomputeFloats = false) override;
 
     void deleteLineBoxTree() final;
 
-    LayoutUnit availableLogicalWidthForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = 0) const
+    LayoutUnit availableLogicalWidthForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = LayoutUnit()) const
     {
-        return max<LayoutUnit>(0, logicalRightOffsetForLine(position, indentText, logicalHeight) - logicalLeftOffsetForLine(position, indentText, logicalHeight));
+        return max<LayoutUnit>(LayoutUnit(), logicalRightOffsetForLine(position, indentText, logicalHeight) - logicalLeftOffsetForLine(position, indentText, logicalHeight));
     }
-    LayoutUnit logicalRightOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = 0) const
+    LayoutUnit logicalRightOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = LayoutUnit()) const
     {
         return logicalRightOffsetForLine(position, logicalRightOffsetForContent(), indentText, logicalHeight);
     }
-    LayoutUnit logicalLeftOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = 0) const
+    LayoutUnit logicalLeftOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = LayoutUnit()) const
     {
         return logicalLeftOffsetForLine(position, logicalLeftOffsetForContent(), indentText, logicalHeight);
     }
-    LayoutUnit startOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = 0) const
+    LayoutUnit startOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = LayoutUnit()) const
     {
         return style()->isLeftToRightDirection() ? logicalLeftOffsetForLine(position, indentText, logicalHeight)
             : logicalWidth() - logicalRightOffsetForLine(position, indentText, logicalHeight);
     }
-    LayoutUnit endOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = 0) const
+    LayoutUnit endOffsetForLine(LayoutUnit position, IndentTextOrNot indentText, LayoutUnit logicalHeight = LayoutUnit()) const
     {
         return !style()->isLeftToRightDirection() ? logicalLeftOffsetForLine(position, indentText, logicalHeight)
             : logicalWidth() - logicalRightOffsetForLine(position, indentText, logicalHeight);
     }
 
     // FIXME-BLOCKFLOW: Move this into LayoutBlockFlow once there are no calls
     // in LayoutBlock. http://crbug.com/393945, http://crbug.com/302024
     using LayoutBlock::lineBoxes;
     using LayoutBlock::firstLineBox;
     using LayoutBlock::lastLineBox;
@@ skipping 330 matching lines @@
             , m_multiColumnFlowThread(nullptr)
             , m_lineBreakToAvoidWidow(-1)
             , m_didBreakAtLineToAvoidWidow(false)
             , m_discardMarginBefore(false)
             , m_discardMarginAfter(false)
         {
         }
 
         static LayoutUnit positiveMarginBeforeDefault(const LayoutBlockFlow* block)
         {
-            return std::max<LayoutUnit>(block->marginBefore(), 0);
+            return std::max<LayoutUnit>(block->marginBefore(), LayoutUnit());

[eae, 2016/01/29 03:38:11]

No need for template specification if you specify the type for the second
argument.

std::max(block->marginBefore(), LayoutUnit());

Given how common this is we might be better off with a helper function here.

Something like ensurePositive or clampToZero. Could be a static function or a
method on LayoutUnit.

block->marginBefore().clampToZero();

[leviw_travelin_and_unemployed, 2016/01/29 03:47:27]

Makes sense.

         }
         static LayoutUnit negativeMarginBeforeDefault(const LayoutBlockFlow* block)
         {
-            return std::max<LayoutUnit>(-block->marginBefore(), 0);
+            return std::max<LayoutUnit>(-block->marginBefore(), LayoutUnit());
         }
         static LayoutUnit positiveMarginAfterDefault(const LayoutBlockFlow* block)
         {
-            return std::max<LayoutUnit>(block->marginAfter(), 0);
+            return std::max<LayoutUnit>(block->marginAfter(), LayoutUnit());
         }
         static LayoutUnit negativeMarginAfterDefault(const LayoutBlockFlow* block)
         {
-            return std::max<LayoutUnit>(-block->marginAfter(), 0);
+            return std::max<LayoutUnit>(-block->marginAfter(), LayoutUnit());
         }
 
         MarginValues m_margins;
         LayoutUnit m_paginationStrutPropagatedFromChild;
 
         LayoutMultiColumnFlowThread* m_multiColumnFlowThread;
 
         int m_lineBreakToAvoidWidow;
         bool m_didBreakAtLineToAvoidWidow : 1;
         bool m_discardMarginBefore : 1;
@@ skipping 113 matching lines @@
 
 // END METHODS DEFINED IN LayoutBlockFlowLine
 
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlockFlow, isLayoutBlockFlow());
 
 } // namespace blink
 
 #endif // LayoutBlockFlow_h