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

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index 84f11e672d2eb3c9686e9e5df2477c6fd974017a..f1b1af12aac9694dacd1953fb488e9ddf537b6f4 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -2347,8 +2347,7 @@ bool RenderBox::sizesLogicalWidthToFitContent(SizeType widthType) const
     // 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())
@@ -2357,6 +2356,15 @@ bool RenderBox::sizesLogicalWidthToFitContent(SizeType widthType) const
     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();
@@ -3479,7 +3487,16 @@ void RenderBox::computePositionedLogicalWidthUsing(Length logicalWidth, const Re
         } 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);