[GCM] Wiring heartbeat interval calls to GCMDriver

components/gcm_driver/gcm_client.h

Index: components/gcm_driver/gcm_client.h
diff --git a/components/gcm_driver/gcm_client.h b/components/gcm_driver/gcm_client.h
index cd804b2a520300cf9011700f10d3d902f609a32a..867223391241d3179ffffb2f818ad69a9d06e5a6 100644
--- a/components/gcm_driver/gcm_client.h
+++ b/components/gcm_driver/gcm_client.h
@@ -320,6 +320,14 @@ class GCMClient {
   // Retrieves the Instance ID data for a specific app from the persistent
   // store.
   virtual std::string GetInstanceIDData(const std::string& app_id) = 0;
+
+  // Gets and sets custom heartbeat interval for the MCS connection.
+  // |scope| is used to identify the component that requests a custom interval
+  // to be set, and allows that component to later revoke the setting. It should
+  // be unique.
+  virtual void AddHeartbeatInterval(const std::string& scope,
+                                    int interval_ms) = 0;
+  virtual void RemoveHeartbeatInterval(const std::string& scope) = 0;
 };
 
 }  // namespace gcm