Use a new Supplement constructor for Supplement<Document> (Part 1)

third_party/WebKit/Source/core/xml/DocumentXSLT.h

Index: third_party/WebKit/Source/core/xml/DocumentXSLT.h
diff --git a/third_party/WebKit/Source/core/xml/DocumentXSLT.h b/third_party/WebKit/Source/core/xml/DocumentXSLT.h
index a1a72b34ba7f804f21907147be1c931c1d0b0e98..1b0971e61c55497d500a8afa5f0d4a13e4e90196 100644
--- a/third_party/WebKit/Source/core/xml/DocumentXSLT.h
+++ b/third_party/WebKit/Source/core/xml/DocumentXSLT.h
@@ -29,7 +29,7 @@ class DocumentXSLT final : public GarbageCollected<DocumentXSLT>,
     m_transformSourceDocument = document;
   }
 
-  static DocumentXSLT& from(Supplementable<Document>&);
+  static DocumentXSLT& from(Document&);
   static const char* supplementName();
 
   // The following static methods don't use any instance of DocumentXSLT.
@@ -46,7 +46,7 @@ class DocumentXSLT final : public GarbageCollected<DocumentXSLT>,
   DECLARE_VIRTUAL_TRACE();
 
  private:
-  DocumentXSLT();
+  explicit DocumentXSLT(Document&);
 
   Member<Document> m_transformSourceDocument;
 };