[GCM] Add ConnectionListener support, and hook up to debug page

google_apis/gcm/engine/connection_factory.h

Index: google_apis/gcm/engine/connection_factory.h
diff --git a/google_apis/gcm/engine/connection_factory.h b/google_apis/gcm/engine/connection_factory.h
index 393d6a9ca247d32030abd1baa9170f3913f9c8b4..1888c19f8b59e18f22dfbd4ece906920db916995 100644
--- a/google_apis/gcm/engine/connection_factory.h
+++ b/google_apis/gcm/engine/connection_factory.h
@@ -9,6 +9,12 @@
 #include "google_apis/gcm/base/gcm_export.h"
 #include "google_apis/gcm/engine/connection_handler.h"
 
+class GURL;
+
+namespace net {
+class IPEndPoint;
+}
+
 namespace mcs_proto {
 class LoginRequest;
 }
@@ -36,6 +42,22 @@ class GCM_EXPORT ConnectionFactory {
     CONNECTION_RESET_COUNT,
   };
 
+  // Listener interface to be notified of endpoint connection events.
+  class ConnectionListener {
+   public:
+    ConnectionListener();
+    virtual ~ConnectionListener();
+
+    // Notifies the listener that GCM has performed a handshake with and is now
+    // actively connected to |current_endpoint|. |socket_ip| is the resolved
+    // ip address/port through which the connection is being made.
+    virtual void OnConnected(const GURL& current_endpoint,
+                             const net::IPEndPoint& socket_ip) = 0;
+
+    // Notifies the listener that the connection has been interrupted.
+    virtual void OnDisconnected() = 0;
+  };
+
   ConnectionFactory();
   virtual ~ConnectionFactory();
 
@@ -66,6 +88,9 @@ class GCM_EXPORT ConnectionFactory {
   // connection.
   virtual bool IsEndpointReachable() const = 0;
 
+  // Returns a debug string describing the connection state.
+  virtual std::string GetConnectionStateString() const = 0;
+
   // If in backoff, the time at which the next retry will be made. Otherwise,
   // a null time, indicating either no attempt to connect has been made or no
   // backoff is in progress.
@@ -76,6 +101,11 @@ class GCM_EXPORT ConnectionFactory {
   // If the last connection was made within kConnectionResetWindowSecs, the old
   // backoff is restored, else a new backoff kicks off.
   virtual void SignalConnectionReset(ConnectionResetReason reason) = 0;
+
+  // Sets the current connection listener. Only one listener is supported at a
+  // time, and the listener must either outlive the connection factory or
+  // call SetConnectionListener(NULL) upon destruction.
+  virtual void SetConnectionListener(ConnectionListener* listener) = 0;
 };
 
 }  // namespace gcm