Use shrink-to-fit for width for Button, input, select, textarea, and legend treat width value of 'a…

Source/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 2329 matching lines @@
     // that don't stretch their kids lay out their children at their intrinsic widths.
     // FIXME: Think about block-flow here.
     // https://bugs.webkit.org/show_bug.cgi?id=46473
     if (parent()->isDeprecatedFlexibleBox() && (parent()->style()->boxOrient() == HORIZONTAL || parent()->style()->boxAlign() != BSTRETCH))
         return true;
 
     // Button, input, select, textarea, and legend treat width value of 'auto' as 'intrinsic' unless it's in a
     // stretching column flexbox.
     // FIXME: Think about block-flow here.
     // https://bugs.webkit.org/show_bug.cgi?id=46473
-    if (logicalWidth.type() == Auto && !isStretchingColumnFlexItem(this) && node() && (node()->hasTagName(inputTag)
-        || node()->hasTagName(selectTag) || node()->hasTagName(buttonTag) || isHTMLTextAreaElement(node()) || node()->hasTagName(legendTag)))
+    if (logicalWidth.type() == Auto && !isStretchingColumnFlexItem(this) && isElementWithIntrinsicWidth())
         return true;
 
     if (isHorizontalWritingMode() != containingBlock()->isHorizontalWritingMode())
         return true;
 
     return false;
 }
 
+bool RenderBox::isElementWithIntrinsicWidth() const
+{
+    if (node() && (node()->hasTagName(inputTag) || node()->hasTagName(selectTag) || node()->hasTagName(buttonTag)
+        || isHTMLTextAreaElement(node()) || node()->hasTagName(legendTag)))
+        return true;
+
+    return false;
+}
+
 void RenderBox::computeInlineDirectionMargins(RenderBlock* containingBlock, LayoutUnit containerWidth, LayoutUnit childWidth, LayoutUnit& marginStart, LayoutUnit& marginEnd) const
 {
     const RenderStyle* containingBlockStyle = containingBlock->style();
     Length marginStartLength = style()->marginStartUsing(containingBlockStyle);
     Length marginEndLength = style()->marginEndUsing(containingBlockStyle);
     RenderView* renderView = view();
 
     if (isFloating() || isInline()) {
         // Inline blocks/tables and floats don't have their margins increased.
         marginStart = minimumValueForLength(marginStartLength, containerWidth, renderView);
@@ skipping 1102 matching lines @@
             LayoutUnit preferredMinWidth = minPreferredLogicalWidth() - bordersPlusPadding;
             LayoutUnit availableWidth = availableSpace - logicalLeftValue;
             computedValues.m_extent = min(max(preferredMinWidth, availableWidth), preferredWidth);
         } else if (logicalLeftIsAuto && !logicalWidthIsAuto && !logicalRightIsAuto) {
             // RULE 4: (solve for left)
             computedValues.m_extent = adjustContentBoxLogicalWidthForBoxSizing(valueForLength(logicalWidth, containerLogicalWidth, renderView));
             logicalLeftValue = availableSpace - (computedValues.m_extent + valueForLength(logicalRight, containerLogicalWidth, renderView));
         } else if (!logicalLeftIsAuto && logicalWidthIsAuto && !logicalRightIsAuto) {
             // RULE 5: (solve for width)
             logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth, renderView);
-            computedValues.m_extent = availableSpace - (logicalLeftValue + valueForLength(logicalRight, containerLogicalWidth, renderView));
+            // Use shrink-to-fit for width for Button, input, select, textarea, and legend treat width value of
+            // 'auto' as 'intrinsic'.
+            if (isElementWithIntrinsicWidth()) {
+                LayoutUnit preferredWidth = maxPreferredLogicalWidth() - bordersPlusPadding;
+                LayoutUnit preferredMinWidth = minPreferredLogicalWidth() - bordersPlusPadding;
+                LayoutUnit availableWidth = availableSpace - logicalLeftValue;
+                computedValues.m_extent = min(max(preferredMinWidth, availableWidth), preferredWidth);

[cbiesinger, 2013/10/09 17:13:38]

Is there a reasonable way to share this code with the RULE 3 case above? Maybe a
function shrinkToFitWidth()?

[pals, 2013/10/10 05:30:54]

Done.

+            } else {
+                computedValues.m_extent = availableSpace - (logicalLeftValue + valueForLength(logicalRight, containerLogicalWidth, renderView));
+            }
         } else if (!logicalLeftIsAuto && !logicalWidthIsAuto && logicalRightIsAuto) {
             // RULE 6: (no need solve for right)
             logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth, renderView);
             computedValues.m_extent = adjustContentBoxLogicalWidthForBoxSizing(valueForLength(logicalWidth, containerLogicalWidth, renderView));
         }
     }
 
     // Use computed values to calculate the horizontal position.
 
     // FIXME: This hack is needed to calculate the  logical left position for a 'rtl' relatively
@@ skipping 1290 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore