Snap inline box boundaries to layout units during line breaking.

third_party/WebKit/Source/core/layout/line/LineWidth.h

 /*
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 50 matching lines @@
     float availableWidth() const { return m_availableWidth; }
     float trailingWhitespaceWidth() const { return m_trailingWhitespaceWidth; }
 
     void updateAvailableWidth(LayoutUnit minimumHeight = 0);
     void shrinkAvailableWidthForNewFloatIfNeeded(const FloatingObject&);
     void addUncommittedWidth(float delta) { m_uncommittedWidth += delta; }
     void commit();
     void applyOverhang(LineLayoutRubyRun, LineLayoutItem startLayoutItem, LineLayoutItem endLayoutItem);
     void fitBelowFloats(bool isFirstLine = false);
     void setTrailingWhitespaceWidth(float width) { m_trailingWhitespaceWidth = width; }
+    void snapUncommittedWidth() { m_uncommittedWidth = LayoutUnit(m_uncommittedWidth).toFloat(); }

[eae, 2015/09/29 14:50:00]

Is the currentWidth already snapped? What about snapping currentWidth?

[szager1, 2015/09/29 16:48:32]

Based on conversation with eae: currentWidth is used while laying out words in a
single LayoutText, and at that time, it's expected that offsets are not snapped.
 Snapping currentWidth() isn't obviously wrong, but it's not obviously right
either.  Since the layout tests are passing without that change, I'm going to
leave it out of this patch.

I added a comment to the code about this.

 
     bool shouldIndentText() const { return m_shouldIndentText == IndentText; }
 
 private:
     void computeAvailableWidthFromLeftAndRight();
     void updateLineDimension(LayoutUnit newLineTop, LayoutUnit newLineWidth, const float& newLineLeft, const float& newLineRight);
     void wrapNextToShapeOutside(bool isFirstLine);
 
     LineLayoutBlockFlow m_block;
     float m_uncommittedWidth;
     float m_committedWidth;
     float m_overhangWidth; // The amount by which |m_availableWidth| has been inflated to account for possible contraction due to ruby overhang.
     float m_trailingWhitespaceWidth;
     float m_left;
     float m_right;
     float m_availableWidth;
     bool m_isFirstLine;
     IndentTextOrNot m_shouldIndentText;
 };
 
 }
 
 #endif // LineWidth_h