Add support of leader_point in NGLayoutOpportunityIterator.

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

Index: third_party/WebKit/Source/core/layout/ng/ng_units.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_units.cc b/third_party/WebKit/Source/core/layout/ng/ng_units.cc
index 71e9f0b0dea3928c3ff3da73cc714cc119753bea..8fba52f9ad8c5aba69b3afe9daf962dbdba2ea5b 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_units.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_units.cc
@@ -107,6 +107,30 @@ NGLogicalOffset& NGLogicalOffset::operator+=(const NGLogicalOffset& other) {
   return *this;
 }
 
+bool NGLogicalOffset::operator>(const NGLogicalOffset& other) const {
+  return inline_offset > other.inline_offset &&
+         block_offset > other.block_offset;
+}
+
+bool NGLogicalOffset::operator>=(const NGLogicalOffset& other) const {
+  return inline_offset >= other.inline_offset &&
+         block_offset >= other.block_offset;
+}
+
+bool NGLogicalOffset::operator<(const NGLogicalOffset& other) const {
+  return inline_offset < other.inline_offset &&
+         block_offset < other.block_offset;
+}
+
+bool NGLogicalOffset::operator<=(const NGLogicalOffset& other) const {
+  return inline_offset <= other.inline_offset &&
+         block_offset <= other.block_offset;
+}
+
+String NGLogicalOffset::ToString() const {
+  return String::format("%dx%d", inline_offset.toInt(), block_offset.toInt());
+}
+
 bool NGBoxStrut::IsEmpty() const {
   return *this == NGBoxStrut();
 }