Issue #1370 - Part 3: Implement `content` keyword for `flex-basis` property

Partially based on https://bugzilla.mozilla.org/show_bug.cgi?id=1105111

1 files changed, 14 insertions, 2 deletions

diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index 99442e681f..141c148673 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -4647,11 +4647,23 @@ nsFrame::SetCoordToFlexBasis(bool aIsInlineFlexItem,
     return;
   }
 
+  const nsStyleCoord* newCoord = aFlexBasis;
+
+  // Having 'content' as the value of the 'flex-basis' property is
+  // equivalent to setting both 'flex-basis' and the main size
+  // properties to 'auto', which is why a dummy 'auto' value will
+  // be used here for the main size property.
+  if (aFlexBasis->GetUnit() == eStyleUnit_Enumerated &&
+      aFlexBasis->GetIntValue() == NS_STYLE_FLEX_BASIS_CONTENT) {
+    static const nsStyleCoord autoStyleCoord(eStyleUnit_Auto);
+    newCoord = &autoStyleCoord;
+  }
+
   // Override whichever styleCoord is in the flex container's main axis
   if (aIsInlineFlexItem) {
-    *aInlineStyle = aFlexBasis;
+    *aInlineStyle = newCoord;
   } else {
-    *aBlockStyle = aFlexBasis;
+    *aBlockStyle = newCoord;
   }
 }