Add macros to define comparison operators to compare by reference or pointer interchangeably

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index e696a29c813d8c98b9258575c86151668ffe76d7..a3122d838fb44c7d72e9545d9f86881477f1dcc1 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -1289,13 +1289,8 @@ private:
     TemporaryChange<bool> m_disabler;
 };
 
-// Allow equality comparisons of RenderObject's by reference or pointer, interchangeably.
-inline bool operator==(const RenderObject& a, const RenderObject& b) { return &a == &b; }
-inline bool operator==(const RenderObject& a, const RenderObject* b) { return &a == b; }
-inline bool operator==(const RenderObject* a, const RenderObject& b) { return a == &b; }
-inline bool operator!=(const RenderObject& a, const RenderObject& b) { return !(a == b); }
-inline bool operator!=(const RenderObject& a, const RenderObject* b) { return !(a == b); }
-inline bool operator!=(const RenderObject* a, const RenderObject& b) { return !(a == b); }
+// Allow equality comparisons of RenderObjects by reference or pointer, interchangeably.
+DEFINE_COMPARISON_OPERATORS_WITH_REFERENCES(RenderObject)
 
 inline bool RenderObject::documentBeingDestroyed() const
 {