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 DidStartProvisionalLoadForFrame(
+      content::RenderFrameHost* render_frame_host,
+      const GURL& validated_url,
+      bool is_error_page,
+      bool is_iframe_srcdoc) override;
+  void DidFailProvisionalLoad(content::RenderFrameHost* render_frame_host,

[Pete Williamson, 2016/02/25 18:05:31]

nit: It might make the file easier to read if the two functions were indented
the same way.  I suspect the first one has to be indented the way it is because
the first argument is too long, it would be nice if we could indent the second
one like the first, with the first argument starting on a new line, and the
others lined up beneath it.

[jianli, 2016/02/25 21:34:52]

Done.

+                              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_