Serve offline page for online URL on disconnected or bad networks

chrome/browser/android/offline_pages/offline_page_request_interceptor.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_request_interceptor.h"
+
+#include "base/supports_user_data.h"
+#include "chrome/browser/android/offline_pages/offline_page_request_job.h"
+
+namespace offline_pages {
+
+OfflinePageRequestInterceptor::OfflinePageRequestInterceptor(void* profile_id)
+    : profile_id_(profile_id) {
+  DCHECK(profile_id);
+}
+
+OfflinePageRequestInterceptor::~OfflinePageRequestInterceptor() {}
+
+net::URLRequestJob* OfflinePageRequestInterceptor::MaybeInterceptRequest(
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate) const {
+  return OfflinePageRequestJob::Create(profile_id_, request, network_delegate);

[mmenke, 2016/08/19 15:04:09]

I don't think we need to intercept every single request.  That slows down every
request made by the network just for this feature, even if it typically won't be
much.  Could we early reject most requests pages?

[jianli, 2016/08/19 19:34:56]

I've already put the rejection logic in OfflinePageRequestJob::Create which may
return nullptr.

Added comment to make this clear.

+}
+
+}  // namespace offline_pages