Remove unused code.

chrome/browser/android/offline_pages/recent_tab_helper.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 CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 24 matching lines @@
 
   // content::WebContentsObserver
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;
   void DocumentAvailableInMainFrame() override;
   void DocumentOnLoadCompletedInMainFrame() override;
 
   // SnapshotController::Client
   void StartSnapshot() override;
 
-  // Test support.
-  // A factory that supplies the instances of an OfflinePageArchiver.
-  // This is used for testing, where we want to use a specific mock.
-  class TestArchiveFactory {
-   public:
-    virtual ~TestArchiveFactory() {}
-    virtual std::unique_ptr<OfflinePageArchiver> CreateArchiver(
-        content::WebContents* web_contents) = 0;
-  };
-
-
   // Delegate that is used by RecentTabHelper to get external dependencies.
   // Default implementation lives in .cc file, while tests provide an override.
   class Delegate {
    public:
     virtual ~Delegate() {}
     virtual std::unique_ptr<OfflinePageArchiver> CreatePageArchiver(
         content::WebContents* web_contents) = 0;
     virtual scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() = 0;
     // There is no expectations that tab_id is always present.
     virtual bool GetTabId(content::WebContents* web_contents, int* tab_id) = 0;
@@ skipping 29 matching lines @@
 
   std::unique_ptr<Delegate> delegate_;
 
   base::WeakPtrFactory<RecentTabHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RecentTabHelper);
 };
 
 }  // namespace offline_pages
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_