[Offline pages] Create offliner that uses background loader

components/offline_pages/content/background_loader/background_loader_contents.h

 // Copyright 2016 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_OFFLINE_PAGES_CONTENT_BACKGROUND_LOADER_BACKGROUND_LOADER_CONTENTS_H_
 #define COMPONENTS_OFFLINE_PAGES_CONTENT_BACKGROUND_LOADER_BACKGROUND_LOADER_CONTENTS_H_
 
 #include <string>
 
 #include "content/public/browser/web_contents_delegate.h"
@@ skipping 10 matching lines @@
 // a renderer but does not have any visible display.
 class BackgroundLoaderContents : public content::WebContentsDelegate {
  public:
   // Creates BackgroundLoaderContents with specified |browser_context|. Uses
   // default session storage space.
   explicit BackgroundLoaderContents(content::BrowserContext* browser_context);
   ~BackgroundLoaderContents() override;
 
   // Loads the URL in a WebContents. Will call observe on all current observers
   // with the created WebContents.
-  void LoadPage(const GURL& url);
+  virtual void LoadPage(const GURL& url);
   // Cancels loading of the current page. Calls Close() on internal WebContents.
-  void Cancel();
+  virtual void Cancel();
   // Returns the inner web contents.
   content::WebContents* web_contents() { return web_contents_.get(); }
 
   // content::WebContentsDelegate implementation:
   bool IsNeverVisible(content::WebContents* web_contents) override;
   void CloseContents(content::WebContents* source) override;
   bool ShouldSuppressDialogs(content::WebContents* source) override;
   bool ShouldFocusPageAfterCrash() override;
   void CanDownload(const GURL& url,
                    const std::string& request_method,
@@ skipping 26 matching lines @@
   void RequestMediaAccessPermission(
       content::WebContents* contents,
       const content::MediaStreamRequest& request,
       const content::MediaResponseCallback& callback) override;
   bool CheckMediaAccessPermission(content::WebContents* contents,
                                   const GURL& security_origin,
                                   content::MediaStreamType type) override;
 
  private:
   friend class BackgroundLoaderContentsTest;
+  friend class BackgroundLoaderContentsStub;
+
   BackgroundLoaderContents();
 
   std::unique_ptr<content::WebContents> web_contents_;
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundLoaderContents);
 };
 
 }  // namespace background_loader
 #endif  // COMPONENTS_OFFLINE_PAGES_CONTENT_BACKGROUND_LOADER_BACKGROUND_LOADER_CONTENTS_H_