Add the JNI code in order to let Java use the InterestsFetcher.

chrome/browser/interests/interests_fetcher.h

 // Copyright 2015 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 CHROME_BROWSER_INTERESTS_INTERESTS_FETCHER_H_
 #define CHROME_BROWSER_INTERESTS_INTERESTS_FETCHER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 27 matching lines @@
     Interest(const std::string& name, const GURL& image_url, double relevance);
     ~Interest();
 
     bool operator==(const Interest& interest) const;
 
     std::string name;
     GURL image_url;
     double relevance;
   };
 
-  using InterestsCallback = base::Callback<void(const std::vector<Interest>&)>;
+  using InterestsCallback =
+      base::Callback<void(scoped_ptr<std::vector<Interest>>)>;
 
   InterestsFetcher(OAuth2TokenService* oauth2_token_service,
                    const std::string& account_id,
                    net::URLRequestContextGetter* context);
 
   ~InterestsFetcher() override;
 
   static scoped_ptr<InterestsFetcher> CreateFromProfile(Profile* profile);
 
   void FetchInterests(const InterestsCallback& callback);
 
  private:
   // net::URLFetcherDelegate implementation.
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
   // OAuth2TokenService::Consumer implementation.
   void OnGetTokenSuccess(const OAuth2TokenService::Request* request,
                          const std::string& access_token,
                          const base::Time& experiation_time) override;
   void OnGetTokenFailure(const OAuth2TokenService::Request* request,
                          const GoogleServiceAuthError& error) override;
 
   void StartOAuth2Request();
   OAuth2TokenService::ScopeSet GetApiScopes();
   scoped_ptr<net::URLFetcher> CreateFetcher();
 
   // Parse the json response.
-  std::vector<Interest> ExtractInterests(const std::string& response);
+  scoped_ptr<std::vector<Interest>>
+      ExtractInterests(const std::string& response);
 
   InterestsCallback callback_;
   scoped_ptr<net::URLFetcher> fetcher_;
   std::string account_id_;
   net::URLRequestContextGetter* url_request_context_;
   bool access_token_expired_;
   std::string access_token_;
 
   scoped_ptr<OAuth2TokenService::Request> oauth_request_;
   OAuth2TokenService* token_service_;
 
   DISALLOW_COPY_AND_ASSIGN(InterestsFetcher);
 };
 
 #endif  // CHROME_BROWSER_INTERESTS_INTERESTS_FETCHER_H_