Switch between online and offline version per network connection

chrome/browser/android/offline_pages/offline_page_tab_helper.cc

+// 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.
+
+#include "chrome/browser/android/offline_pages/offline_page_tab_helper.h"
+
+#include "base/logging.h"
+#include "chrome/browser/android/offline_pages/offline_page_utils.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+#include "net/base/net_errors.h"
+#include "net/base/network_change_notifier.h"
+
+namespace {
+
+bool IsOnline() {
+  enum net::NetworkChangeNotifier::ConnectionType connection =
+      net::NetworkChangeNotifier::GetConnectionType();
+  return connection != net::NetworkChangeNotifier::CONNECTION_NONE &&

[Pete Williamson, 2016/02/23 23:13:47]

Let's replace this IsOnline check with NetworkChangeNotifier.isOnline().  It
turns out that BLUETOOTH actually means connnected to the internet via
BLUETOOTH, not just paired with a watch or earphones.

+         connection != net::NetworkChangeNotifier::CONNECTION_BLUETOOTH;
+}
+
+}
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(OfflinePageTabHelper);
+
+OfflinePageTabHelper::~OfflinePageTabHelper() {}
+
+OfflinePageTabHelper::OfflinePageTabHelper(content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+}
+
+void OfflinePageTabHelper::DidStartProvisionalLoadForFrame(
+    content::RenderFrameHost* render_frame_host,
+    const GURL& validated_url,
+    bool is_error_page,
+    bool is_iframe_srcdoc) {
+  if (!IsOnline() ||

[Pete Williamson, 2016/02/23 23:13:47]

Why return early if we are offline, are we intentionally deferring until the
DidFailProvisionalLoad() callback?  I wonder if the "!" is incorrect here.

[Pete Williamson, 2016/02/24 00:35:33]

Ah, nevermind, I see what is going on now, this is to load the online version of
a page if we enter the offline URL but are online.

+      render_frame_host->GetParent() != nullptr) {
+    return;
+  }
+
+  GURL online_url = offline_pages::OfflinePageUtils::GetOnlineURLForOfflineURL(
+      web_contents()->GetBrowserContext(), validated_url);
+  if (!online_url.is_valid())
+    return;
+
+  content::NavigationController::LoadURLParams load_params(online_url);
+  web_contents()->GetController().LoadURLWithParams(load_params);
+}
+
+void OfflinePageTabHelper::DidFailProvisionalLoad(
+    content::RenderFrameHost* render_frame_host,
+    const GURL& validated_url,
+    int error_code,
+    const base::string16& error_description,
+    bool was_ignored_by_handler) {
+  if (error_code != net::ERR_INTERNET_DISCONNECTED ||
+      IsOnline() ||
+      render_frame_host->GetParent() != nullptr) {
+    return;
+  }
+
+  GURL offline_url = offline_pages::OfflinePageUtils::GetOfflineURLForOnlineURL(
+      web_contents()->GetBrowserContext(), validated_url);
+  if (!offline_url.is_valid())
+    return;
+
+  content::NavigationController::LoadURLParams load_params(offline_url);
+  web_contents()->GetController().LoadURLWithParams(load_params);
+}