Update SupportsUserData uses with unique_ptr.

components/pdf/browser/pdf_web_contents_helper.h

 // Copyright (c) 2012 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.
 
 #ifndef COMPONENTS_PDF_BROWSER_PDF_WEB_CONTENTS_HELPER_H_
 #define COMPONENTS_PDF_BROWSER_PDF_WEB_CONTENTS_HELPER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 11 matching lines @@
 namespace pdf {
 
 class PDFWebContentsHelperClient;
 
 // Per-WebContents class to handle PDF messages.
 class PDFWebContentsHelper
     : public content::WebContentsObserver,
       public content::WebContentsUserData<PDFWebContentsHelper>,
       public mojom::PdfService {
  public:
+  ~PDFWebContentsHelper() override;
+
   static void CreateForWebContentsWithClient(
       content::WebContents* contents,
       std::unique_ptr<PDFWebContentsHelperClient> client);
 
  private:
   PDFWebContentsHelper(content::WebContents* web_contents,
                        std::unique_ptr<PDFWebContentsHelperClient> client);
-  ~PDFWebContentsHelper() override;
 
   // mojom::PdfService:
   void HasUnsupportedFeature() override;
   void SaveUrlAs(const GURL& url, const content::Referrer& referrer) override;
   void UpdateContentRestrictions(int32_t content_restrictions) override;
 
   content::WebContentsFrameBindingSet<mojom::PdfService> pdf_service_bindings_;
   std::unique_ptr<PDFWebContentsHelperClient> client_;
 
   DISALLOW_COPY_AND_ASSIGN(PDFWebContentsHelper);
 };
 
 }  // namespace pdf
 
 #endif  // COMPONENTS_PDF_BROWSER_PDF_WEB_CONTENTS_HELPER_H_