[layoutng] Add a function to compute the min- and max-content contribution

third_party/WebKit/Source/core/layout/ng/ng_units.h

Index: third_party/WebKit/Source/core/layout/ng/ng_units.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_units.h b/third_party/WebKit/Source/core/layout/ng/ng_units.h
index ea2eec5c9f5680784eff244879edfede6d29768c..235bf802d0040eec8001b2adecbef7c87dfcccdb 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_units.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_units.h
@@ -22,8 +22,14 @@ struct CORE_EXPORT MinAndMaxContentSizes {
   LayoutUnit min_content;
   LayoutUnit max_content;
   LayoutUnit ShrinkToFit(LayoutUnit available_size) const;
+  bool operator==(const MinAndMaxContentSizes& other) const;
 };
 
+inline std::ostream& operator<<(std::ostream& stream,
+                                const MinAndMaxContentSizes& value) {
+  return stream << "(" << value.min_content << ", " << value.max_content << ")";
+}
+
 struct NGLogicalSize {
   NGLogicalSize() {}
   NGLogicalSize(LayoutUnit inline_size, LayoutUnit block_size)