text: // Copyright 2014 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 CONTENT_RENDERER_FETCHERS_MANIFEST_FETCHER_H_
  #define CONTENT_RENDERER_FETCHERS_MANIFEST_FETCHER_H_
  
  #include <memory>
  #include <string>
  
  #include "base/callback.h"
  #include "base/macros.h"
  #include "content/common/content_export.h"
  #include "third_party/WebKit/public/platform/WebURLResponse.h"
  
  class GURL;
  
  namespace blink {
  class WebFrame;
  }
  
  namespace content {
  
  class AssociatedResourceFetcher;
  
  // Helper class to download a Web Manifest. When an instance is created, the
  // caller need to call Start() and wait for the passed callback to be executed.
  // If the fetch fails, the callback will be called with two empty objects.
  class CONTENT_EXPORT ManifestFetcher {
   public:
    // This will be called asynchronously after the URL has been fetched,
    // successfully or not.  If there is a failure, response and data will both be
    // empty.  |response| and |data| are both valid until the URLFetcher instance
    // is destroyed.
    typedef base::Callback<void(const blink::WebURLResponse& response,
                                const std::string& data)> Callback;
  
    explicit ManifestFetcher(const GURL& url);
    virtual ~ManifestFetcher();
  
    void Start(blink::WebFrame* frame,
               bool use_credentials,
               const Callback& callback);
    void Cancel();
  
   private:
    void OnLoadComplete(const blink::WebURLResponse& response,
                        const std::string& data);
  
    bool completed_;
    Callback callback_;
    std::unique_ptr<AssociatedResourceFetcher> fetcher_;
  
    DISALLOW_COPY_AND_ASSIGN(ManifestFetcher);
  };
  
  } // namespace content
  
  #endif  // CONTENT_RENDERER_FETCHERS_MANIFEST_FETCHER_H_
  