Combine 2 exclusions in Layout Opportunity Tree if they shadow each other

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

Index: third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_tree_node.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_tree_node.cc b/third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_tree_node.cc
index aa211bf5adf7bf24571ceeb3d842638201717e4c..b737001fb829c76a3479175dce47bdf1b6f29c5c 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_tree_node.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_tree_node.cc
@@ -8,7 +8,7 @@ namespace blink {
 
 NGLayoutOpportunityTreeNode::NGLayoutOpportunityTreeNode(
     const NGLogicalRect opportunity)
-    : opportunity(opportunity), exclusion(nullptr) {
+    : opportunity(opportunity), combined_exclusion(nullptr) {
   exclusion_edge.start = opportunity.offset.inline_offset;
   exclusion_edge.end = exclusion_edge.start + opportunity.size.inline_size;
 }
@@ -18,7 +18,15 @@ NGLayoutOpportunityTreeNode::NGLayoutOpportunityTreeNode(
     NGEdge exclusion_edge)
     : opportunity(opportunity),
       exclusion_edge(exclusion_edge),
-      exclusion(nullptr) {}
+      combined_exclusion(nullptr) {}
+
+String NGLayoutOpportunityTreeNode::ToString() const {
+  return String::format("Opportunity: '%s' Exclusion: '%s'",
+                        opportunity.ToString().ascii().data(),
+                        combined_exclusion
+                            ? combined_exclusion->ToString().ascii().data()
+                            : "null");
+}
 
 DEFINE_TRACE(NGLayoutOpportunityTreeNode) {
   visitor->trace(left);