Restructure SDCH layering to allow more separation (observer/1->[0,n]

net/base/sdch_observer.h

+// Copyright 2014 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 NET_BASE_SDCH_OBSERVER_H_
+#define NET_BASE_SDCH_OBSERVER_H_
+
+#include "net/base/net_export.h"
+
+class GURL;
+
+namespace net {
+
+class SdchManager;
+
+// Observer interface for SDCH.  Observers can register with
+// the SdchManager to receive notifications of various SDCH events.
+class NET_EXPORT SdchObserver {
+ public:
+  virtual ~SdchObserver();
+
+  // Notification that SDCH has seen a "Get-Dictionary" header.
+  virtual void OnGetDictionary(SdchManager* manager,
+                               const GURL& request_url,
+                               const GURL& dictionary_url) = 0;
+
+  // Notification that SDCH has received a request to clear all
+  // its dictionaries.
+  virtual void OnClearDictionaries(SdchManager* manager) = 0;
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_SDCH_MANAGER_H_