Make InlineBox::renderer() and related subclass methods return reference.

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 1f4f76c6ce20e76d40be0a0134aeb56df6c73bdd..5de8bc22009cf03aa06277ea7ebfb4486b318304 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -1218,6 +1218,14 @@ private:
     LayoutRect m_newRepaintRect;
 };
 
+// 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); }
+
 inline bool RenderObject::documentBeingDestroyed() const
 {
     return !document().renderer();