Change ContentData::operator== to iterate through whole list.

third_party/WebKit/Source/core/style/ContentData.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2010 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 182 matching lines @@
   QuoteContentData(QuoteType quote) : quote_(quote) {}
 
   ContentData* CloneInternal() const override { return Create(Quote()); }
 
   QuoteType quote_;
 };
 
 DEFINE_CONTENT_DATA_TYPE_CASTS(Quote);
 
 inline bool operator==(const ContentData& a, const ContentData& b) {
-  return a.Equals(b);
-}
+  const ContentData* ptr_a = &a;
+  const ContentData* ptr_b = &b;
 
-inline bool operator!=(const ContentData& a, const ContentData& b) {
-  return !(a == b);
+  while (ptr_a && ptr_b && ptr_a->Equals(*ptr_b)) {
+    ptr_a = ptr_a->Next();
+    ptr_b = ptr_b->Next();
+  }
+
+  return !ptr_a && !ptr_b;
 }
 
 }  // namespace blink
 
 #endif  // ContentData_h