Fix the Download Notifications for Offline Pages to indicate bytes loaded.

chrome/browser/android/offline_pages/prerendering_offliner.h

Index: chrome/browser/android/offline_pages/prerendering_offliner.h
diff --git a/chrome/browser/android/offline_pages/prerendering_offliner.h b/chrome/browser/android/offline_pages/prerendering_offliner.h
index 935d3019f145d8a2c192c960d62bc5f9f8f43b7b..71c1a93a19abe9792878738750613f436292fcf2 100644
--- a/chrome/browser/android/offline_pages/prerendering_offliner.h
+++ b/chrome/browser/android/offline_pages/prerendering_offliner.h
@@ -35,7 +35,8 @@ class PrerenderingOffliner : public Offliner {
 
   // Offliner implementation.
   bool LoadAndSave(const SavePageRequest& request,
-                   const CompletionCallback& callback) override;
+                   const CompletionCallback& completion_callback,
+                   const ProgressCallback& progress_callback) override;
   void Cancel(const CancelCallback& callback) override;
   bool HandleTimeout(const SavePageRequest& request) override;
 
@@ -93,6 +94,7 @@ class PrerenderingOffliner : public Offliner {
   std::unique_ptr<SavePageRequest> pending_request_;
   // Callback to call when pending request completes/fails.
   CompletionCallback completion_callback_;
+  ProgressCallback progress_callback_;
   bool is_low_end_device_;
   // ApplicationStatusListener to monitor if the Chrome moves to the foreground.
   std::unique_ptr<base::android::ApplicationStatusListener> app_listener_;