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google_apis/gcm/gcm_client.h

 // Copyright 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 GOOGLE_APIS_GCM_GCM_CLIENT_H_
 #define GOOGLE_APIS_GCM_GCM_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 60 matching lines @@
   };
 
   // Message being received from the other party.
   struct GCM_EXPORT IncomingMessage {
     IncomingMessage();
     ~IncomingMessage();
 
     MessageData data;
   };
 
+  // Internal states and statistics of a GCM client.
+  struct GCM_EXPORT GCMStatistics {
+   public:
+    GCMStatistics();
+    ~GCMStatistics();
+
+    bool gcm_client_created;
+    std::string gcm_client_state;
+    bool connection_client_created;
+    std::string connection_state;
+  };
+
   // A delegate interface that allows the GCMClient instance to interact with
   // its caller, i.e. notifying asynchronous event.
   class Delegate {
    public:
     // Called when the registration completed successfully or an error occurs.
     // |app_id|: application ID.
     // |registration_id|: non-empty if the registration completed successfully.
     // |result|: the type of the error if an error occured, success otherwise.
     virtual void OnRegisterFinished(const std::string& app_id,
                                     const std::string& registration_id,
@@ skipping 83 matching lines @@
   // called asynchronously upon completion.
   // |app_id|: application ID.
   // |receiver_id|: registration ID of the receiver party.
   // |message|: message to be sent.
   virtual void Send(const std::string& app_id,
                     const std::string& receiver_id,
                     const OutgoingMessage& message) = 0;
 
   // Returns true if GCM becomes ready.
   virtual bool IsReady() const = 0;
+
+  // Get internal states and statistics.
+  virtual void GetStatistics(GCMStatistics* stats) const = 0;

[fgorski, 2014/02/28 19:52:47]

did you consider returning the stats?
e.g.
virtual GCMStatistics GetStatistics() const = 0;

[juyik, 2014/03/01 00:21:57]

Done. It introduces additional copy operations, but for a debug page this might
be fine.

 };
 
 }  // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_GCM_CLIENT_H_