Remove unused code.

chrome/browser/android/offline_pages/recent_tab_helper.h

Index: chrome/browser/android/offline_pages/recent_tab_helper.h
diff --git a/chrome/browser/android/offline_pages/recent_tab_helper.h b/chrome/browser/android/offline_pages/recent_tab_helper.h
index 8d65fa9e9ab4c2539aa1a78ff3e07a6defe7f0c6..32bea5193029e6add144ba18f4e1e21e340a3f78 100644
--- a/chrome/browser/android/offline_pages/recent_tab_helper.h
+++ b/chrome/browser/android/offline_pages/recent_tab_helper.h
@@ -42,17 +42,6 @@ class RecentTabHelper
   // 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 {