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

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/ng/ng_exclusion.h"
 
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 bool NGExclusion::operator==(const NGExclusion& other) const {
   return std::tie(other.rect, other.type) == std::tie(rect, type);
 }
 
 String NGExclusion::ToString() const {
   return String::format("Rect: %s Type: %d", rect.ToString().ascii().data(),
                         type);
 }
 
+bool NGExclusion::MaybeCombineWith(const NGExclusion& other) {
+  if (other.rect.BlockEndOffset() < rect.BlockEndOffset())
+    return false;
+
+  if (other.type != type)
+    return false;
+
+  switch (other.type) {
+    case NGExclusion::kFloatLeft: {
+      if (other.rect.offset == rect.InlineEndBlockStartOffset()) {
+        rect.size = {other.rect.InlineSize() + rect.InlineSize(),
+                     other.rect.BlockSize()};
+        return true;
+      }
+    }
+    case NGExclusion::kFloatRight: {
+      if (rect.offset == other.rect.InlineEndBlockStartOffset()) {
+        rect.offset = other.rect.offset;
+        rect.size = {other.rect.InlineSize() + rect.InlineSize(),
+                     other.rect.BlockSize()};
+        return true;
+      }
+    }
+    default:
+      return false;
+  }
+}
+
 std::ostream& operator<<(std::ostream& stream, const NGExclusion& value) {
   return stream << value.ToString();
 }
 
 NGExclusions::NGExclusions()
     : last_left_float(nullptr), last_right_float(nullptr) {}
 
 NGExclusions::NGExclusions(const NGExclusions& other) {
   for (const auto& exclusion : other.storage)
     Add(*exclusion);
@@ skipping 11 matching lines @@
 inline NGExclusions& NGExclusions::operator=(const NGExclusions& other) {
   storage.clear();
   last_left_float = nullptr;
   last_right_float = nullptr;
   for (const auto& exclusion : other.storage)
     Add(*exclusion);
   return *this;
 }
 
 }  // namespace blink