Adding CopresenceState

components/copresence/public/copresence_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 COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_OBSERVER_H_
+#define COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_OBSERVER_H_
+
+#include <map>
+#include <string>
+#include <vector>

[xiyuan, 2014/12/18 18:10:52]

nit: The above 3 headers seems not used.

[Charlie, 2014/12/19 03:53:33]

Done.

+
+#include "base/macros.h"
+
+namespace copresence {
+
+class Directive;
+struct TransmittedToken;
+struct ReceivedToken;
+
+// Implement this interface to be notified of changes
+// to the state of the copresence component.
+// TODO(ckehoe): Create a LoggingObserver based on this that replaces
+// equivalent logging elsewhere. Then we know what state is being recorded.
+class CopresenceObserver {
+ public:
+  CopresenceObserver() {}
+  virtual ~CopresenceObserver() {}
+
+  // Called when the list of active directives has changed.
+  virtual void DirectivesUpdated() = 0;
+
+  // Called when a token is transmitted.
+  virtual void TokenTransmitted(const TransmittedToken& token) = 0;
+
+  // Called when a token is received.
+  virtual void TokenReceived(const ReceivedToken& token) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CopresenceObserver);

[xiyuan, 2014/12/18 18:10:52]

nit: usually we don't use DISALLOW_COPY_AND_ASSIGN and have default ctor for
interface,

e.g.
https://code.google.com/p/chromium/codesearch#chromium/src/ash/shell_observer.h

[Charlie, 2014/12/19 03:53:33]

Done.

+};
+
+}  // namespace copresence
+
+#endif  // COMPONENTS_COPRESENCE_PUBLIC_COPRESENCE_OBSERVER_H_