Revert of Revert of Adding CopresenceState

components/copresence/copresence_state_impl.h

Index: components/copresence/copresence_state_impl.h
diff --git a/components/copresence/copresence_state_impl.h b/components/copresence/copresence_state_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..2a941bf4105ca41c331ed808ded42e9cb920b3ae
--- /dev/null
+++ b/components/copresence/copresence_state_impl.h
@@ -0,0 +1,72 @@
+// 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_COPRESENCE_STATE_IMPL_H_
+#define COMPONENTS_COPRESENCE_COPRESENCE_STATE_IMPL_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "components/copresence/proto/enums.pb.h"
+#include "components/copresence/public/copresence_state.h"
+
+namespace copresence {
+
+class Directive;
+struct AudioToken;
+struct ReceivedToken;
+struct TransmittedToken;
+
+// This class tracks the internal state of the copresence component
+// for debugging purposes. CopresenceState only allows observation,
+// but this class accepts updates from elsewhere in the component.
+class CopresenceStateImpl final : public CopresenceState {
+ public:
+  CopresenceStateImpl();
+  ~CopresenceStateImpl() override;
+
+  // CopresenceState overrides.
+  void AddObserver(CopresenceObserver* observer) override;
+  void RemoveObserver(CopresenceObserver* observer) override;
+  const std::vector<Directive>& active_directives() const override;
+  const std::map<std::string, TransmittedToken>&
+  transmitted_tokens() const override;
+  const std::map<std::string, ReceivedToken>&
+  received_tokens() const override;
+
+  // Update the current active directives.
+  void UpdateDirectives(const std::vector<Directive>& directives);
+
+  // Report transmitting a token.
+  void UpdateTransmittedToken(const TransmittedToken& token);
+
+  // Report receiving a token.
+  void UpdateReceivedToken(const ReceivedToken& token);
+
+  // Report the token state from the server.
+  void UpdateTokenStatus(const std::string& token_id, TokenStatus status);
+
+ private:
+  // Reconcile the |active_directives_| against |transmitted_tokens_|.
+  void UpdateTransmittingTokens();
+
+  std::vector<Directive> active_directives_;
+
+  // TODO(ckehoe): When we support more mediums, separate tokens by medium.
+  // Otherwise tokens from different mediums could overwrite each other.
+  // TODO(ckehoe): Limit the number of tokens stored.
+  std::map<std::string, TransmittedToken> transmitted_tokens_;
+  std::map<std::string, ReceivedToken> received_tokens_;
+
+  ObserverList<CopresenceObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(CopresenceStateImpl);
+};
+
+}  // namespace copresence
+
+#endif  // COMPONENTS_COPRESENCE_COPRESENCE_STATE_IMPL_H_