Implement offline mode behind a flag

content/browser/loader/offline_policy.h

+// Copyright (c) 2013 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 CONTENT_BROWSER_LOADER_OFFLINE_POLICY
+#define CONTENT_BROWSER_LOADER_OFFLINE_POLICY
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "content/common/content_export.h"
+
+struct ResourceHostMsg_Request;
+
+namespace net {
+class HttpResponseInfo;
+class URLRequest;
+}
+
+namespace content {
+
+// This class controls under what conditions resources will be fetched
+// from cache even if stale rather than from the network.  For example,
+// one policy would be that if requests for a particular route (e.g. "tab")
+// is unable to reach the server, other requests made with the same route
+// can be loaded from cache without first requiring a network timeout.
+//
+// There is a single OfflinePolicy object per user navigation unit
+// (generally a tab).
+class CONTENT_EXPORT OfflinePolicy {
+ public:
+  OfflinePolicy();
+  ~OfflinePolicy();
+
+  // Return any additional load flags to be ORed for a request from
+  // this route with the given |resource_type|.  |reset_state| indicates
+  // that this request should reinitialized the internal state for this
+  // policy object (e.g. in the case of a main frame load).
+  int GetAdditionalLoadFlags(int current_flags, bool reset_state);
+
+  // Incorporate online/offline information from a completed request.
+  void UpdateStateForCompletedRequest(
+      const net::HttpResponseInfo& response_info);
+
+private:
+  enum State { INIT, ONLINE, OFFLINE };
+
+  bool enabled_;
+  State state_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePolicy);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_OFFLINE_POLICY