Switch between online and offline version per network connection

chrome/browser/android/offline_pages/offline_page_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_OFFLINE_PAGE_TAB_HELPER_H_
+#define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_TAB_HELPER_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+#include "url/gurl.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace offline_pages {
+
+// Per-tab class to manage switch between online version and offline version.
+class OfflinePageTabHelper :
+    public content::WebContentsObserver,
+    public content::WebContentsUserData<OfflinePageTabHelper> {
+ public:
+  ~OfflinePageTabHelper() override;
+
+ private:
+  friend class content::WebContentsUserData<OfflinePageTabHelper>;
+  friend class OfflinePageTabHelperTest;
+
+  explicit OfflinePageTabHelper(content::WebContents* web_contents);
+
+  // Overridden from content::WebContentsObserver:
+  void DidStartNavigation(
+      content::NavigationHandle* navigation_handle) override;
+  void DidFailProvisionalLoad(
+      content::RenderFrameHost* render_frame_host,
+      const GURL& validated_url,
+      int error_code,
+      const base::string16& error_description,
+      bool was_ignored_by_handler) override;
+
+  void RedirectFromOfflineToOnline(const GURL& online_url);
+  void RedirectFromOnlineToOffline(const GURL& offline_url);
+
+  GURL last_redirect_from_url_;
+  base::WeakPtrFactory<OfflinePageTabHelper> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePageTabHelper);
+};
+
+}  // namespace offline_pages
+
+#endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_TAB_HELPER_H_