Make fixed-width elements not center by default.

sky/engine/core/rendering/RenderBox.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 1630 matching lines @@
     LayoutUnit marginStartWidth = minimumValueForLength(marginStartLength, containerWidth);
     LayoutUnit marginEndWidth = minimumValueForLength(marginEndLength, containerWidth);
 
     // CSS 2.1 (10.3.3): "If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width'
     // (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then any 'auto'
     // values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero.
     LayoutUnit marginBoxWidth = childWidth + (!style()->width().isAuto() ? marginStartWidth + marginEndWidth : LayoutUnit());
 
     // CSS 2.1: "If both 'margin-left' and 'margin-right' are 'auto', their used values are equal. This horizontally centers the element
     // with respect to the edges of the containing block."
-    if ((marginStartLength.isAuto() && marginEndLength.isAuto() && marginBoxWidth < containerWidth)
-        || (!marginStartLength.isAuto() && !marginEndLength.isAuto())) {
+    if (marginStartLength.isAuto() && marginEndLength.isAuto() && marginBoxWidth < containerWidth) {
         // Other browsers center the margin box for align=center elements so we match them here.
         LayoutUnit centeredMarginBoxStart = std::max<LayoutUnit>(0, (containerWidth - childWidth - marginStartWidth - marginEndWidth) / 2);
         marginStart = centeredMarginBoxStart + marginStartWidth;
         marginEnd = containerWidth - childWidth - marginStart + marginEndWidth;
         return;
     }
 
     // CSS 2.1: "If there is exactly one value specified as 'auto', its used value follows from the equality."
     if (marginEndLength.isAuto() && marginBoxWidth < containerWidth) {
         marginStart = marginStartWidth;
@@ skipping 1848 matching lines @@
 
 RenderBox::BoxDecorationData::BoxDecorationData(const RenderStyle& style)
 {
     backgroundColor = style.colorIncludingFallback(CSSPropertyBackgroundColor);
     hasBackground = backgroundColor.alpha() || style.hasBackgroundImage();
     ASSERT(hasBackground == style.hasBackground());
     hasBorder = style.hasBorder();
 }
 
 } // namespace blink