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"
+#include "webkit/glue/resource_type.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 the current request.

[darin (slow to review), 2013/04/11 20:01:23]

nit: "for the current request" ... since the parameters do not include an
URLRequest object, might want to revise this text.

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

Done.

+  int GetAdditionalLoadFlags(
+      int current_flags, ResourceType::Type resource_type);
+
+  // Incorporate online/offline information from a completed request.
+  void RequestCompleted(const net::HttpResponseInfo& response_info);

[darin (slow to review), 2013/04/11 20:01:23]

nit: how about method name that better describes the action this method will
take?  how about calling it UpdateStateForCompletedRequest?

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

Done.

+
+private:
+  enum OfflineState { INIT, ONLINE, OFFLINE };

[darin (slow to review), 2013/04/11 20:01:23]

nit: since this class is named OfflinePolicy, you could just name this enum
"State".  No need to repeat the "namespace".

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

Done.

+
+  OfflineState offline_state_;

[darin (slow to review), 2013/04/11 20:01:23]

ditto: could just be named "state_"

[Randy Smith (Not in Mondays), 2013/04/12 14:06:44]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePolicy);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_OFFLINE_POLICY