[css-flexbox] slight improvements to mainSizeForPercentageResolution

third_party/WebKit/Source/core/layout/LayoutFlexibleBox.cpp

 /*
  * Copyright (C) 2011 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
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1091 matching lines @@
 
 LayoutUnit LayoutFlexibleBox::mainSizeForPercentageResolution(const LayoutBox& child)
 {
     // This function implements section 9.8. Definite and Indefinite Sizes, case
     // 2) of the flexbox spec.
     // We need to check for the flexbox to have a definite main size, and for the
     // flex item to have a definite flex basis.
     const Length& flexBasis = flexBasisForChild(child);
     if (!mainAxisLengthIsDefinite(child, flexBasis))
         return LayoutUnit(-1);
-    LayoutUnit mainSize = isColumnFlow() ? computeDefiniteLogicalHeight() : computeDefiniteLogicalWidth();
-    if (mainSize == LayoutUnit(-1))
-        return mainSize;
+    if (!flexBasis.hasPercent()) {
+        // If flex basis had a percentage, our size is guaranteed to be definite or the flex item's
+        // size could not be definite.
+        // Otherwise, we make up a percentage to check whether we have a definite size.
+        // TODO(cbiesinger): cache this somewhere
+        if (!mainAxisLengthIsDefinite(child, Length(0, Percent)))
+            return LayoutUnit(-1);
+    }
 
     if (hasOrthogonalFlow(child))
         return child.hasOverrideLogicalContentHeight() ? child.overrideLogicalContentHeight() : LayoutUnit(-1);
     return child.hasOverrideLogicalContentWidth() ? child.overrideLogicalContentWidth() : LayoutUnit(-1);
 }
 
 LayoutUnit LayoutFlexibleBox::childLogicalHeightForPercentageResolution(const LayoutBox& child)
 {
     if (!hasOrthogonalFlow(child))
         return crossSizeForPercentageResolution(child);
@@ skipping 648 matching lines @@
             ASSERT(child);
             LayoutUnit lineCrossAxisExtent = lineContexts[lineNumber].crossAxisExtent;
             LayoutUnit originalOffset = lineContexts[lineNumber].crossAxisOffset - crossAxisStartEdge;
             LayoutUnit newOffset = contentExtent - originalOffset - lineCrossAxisExtent;
             adjustAlignmentForChild(*child, newOffset - originalOffset);
         }
     }
 }
 
 } // namespace blink