[Offline Pages] Allow BackgroundLoader to track network bytes using prerenderer hook-in.

chrome/browser/android/offline_pages/background_loader_offliner.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_BACKGROUND_LOADER_OFFLINER_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_BACKGROUND_LOADER_OFFLINER_H_
 
 #include <memory>
 
 #include "base/android/application_status_listener.h"
@@ skipping 16 matching lines @@
 // of an offline page. It uses the BackgroundLoader to load the page and the
 // OfflinePageModel to save it. Only one request may be active at a time.
 class BackgroundLoaderOffliner : public Offliner,
                                  public content::WebContentsObserver {
  public:
   BackgroundLoaderOffliner(content::BrowserContext* browser_context,
                            const OfflinerPolicy* policy,
                            OfflinePageModel* offline_page_model);
   ~BackgroundLoaderOffliner() override;
 
+  static BackgroundLoaderOffliner* FromWebContents(
+      content::WebContents* contents);
+
   // Offliner implementation.
   bool LoadAndSave(const SavePageRequest& request,
                    const CompletionCallback& completion_callback,
                    const ProgressCallback& progress_callback) override;
   void Cancel(const CancelCallback& callback) override;
   bool HandleTimeout(const SavePageRequest& request) override;
 
   // WebContentsObserver implementation.
   void DidStopLoading() override;
   void RenderProcessGone(base::TerminationStatus status) override;
   void WebContentsDestroyed() override;
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;
 
   void SetPageDelayForTest(long delay_ms);
+  void OnNetworkBytesChanged(int64_t bytes);
 
  protected:
   // Called to reset internal loader and observer state.
   virtual void ResetState();
 
  private:
   friend class TestBackgroundLoaderOffliner;
+  // Currently there should only be one offliner created...
+  static BackgroundLoaderOffliner* offliner_;

[Dmitry Titov, 2017/03/09 03:15:55]

Perhaps this can be avoided by setting the BackgroundLoaderOffliner as a
webContents::SetUserData()? Then it can be pulled back from WebContents.

See:
https://cs.chromium.org/chromium/src/content/public/browser/web_contents_user...

 
   enum SaveState { NONE, SAVING, DELETE_AFTER_SAVE };
   enum PageLoadState { SUCCESS, RETRIABLE, NONRETRIABLE, DELAY_RETRY };
 
   // Called when the page is ready to be saved.
   void SavePage();
 
   // Called when the page has been saved.
   void OnPageSaved(SavePageResult save_result, int64_t offline_id);
 
   // Called when application state has changed.
   void OnApplicationStateChange(
       base::android::ApplicationState application_state);
   void HandleApplicationStateChangeCancel(const SavePageRequest& request,
                                           int64_t offline_id);
 
   std::unique_ptr<background_loader::BackgroundLoaderContents> loader_;
   // Not owned.
   content::BrowserContext* browser_context_;
   // Not owned.
   OfflinePageModel* offline_page_model_;
   // Tracks pending request, if any.
   std::unique_ptr<SavePageRequest> pending_request_;
   // Callback when pending request completes.
   CompletionCallback completion_callback_;
+  // Callback to report progress.
+  ProgressCallback progress_callback_;
   // ApplicationStatusListener to monitor if Chrome moves to the foreground.
   std::unique_ptr<base::android::ApplicationStatusListener> app_listener_;
   // Whether we are on a low-end device.
   bool is_low_end_device_;
 
   // Save state.
   SaveState save_state_;
   // Page load state.
   PageLoadState page_load_state_;
   // Seconds to delay before taking snapshot.
   long page_delay_ms_;
+  // Network bytes loaded.
+  int64_t network_bytes_;
 
   // Callback for cancel.
   CancelCallback cancel_callback_;
 
   base::WeakPtrFactory<BackgroundLoaderOffliner> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(BackgroundLoaderOffliner);
 };
 
 }  // namespace offline_pages
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_BACKGROUND_LOADER_OFFLINER_H_