[GCM] Wiring heartbeat interval calls to GCMDriver

components/gcm_driver/fake_gcm_client.h

Index: components/gcm_driver/fake_gcm_client.h
diff --git a/components/gcm_driver/fake_gcm_client.h b/components/gcm_driver/fake_gcm_client.h
index c0b03daba88b17fbc856e8cb3c815001808468f5..155c34232e076c303cd5d14283a1ad82e724f4dc 100644
--- a/components/gcm_driver/fake_gcm_client.h
+++ b/components/gcm_driver/fake_gcm_client.h
@@ -60,6 +60,8 @@ class FakeGCMClient : public GCMClient {
                          const std::string& instance_id_data) override;
   void RemoveInstanceIDData(const std::string& app_id) override;
   std::string GetInstanceIDData(const std::string& app_id) override;
+  void AddHeartbeatInterval(const std::string& scope, int interval_ms) override;
+  void RemoveHeartbeatInterval(const std::string& scope) override;
 
   // Initiate the start that has been delayed.
   // Called on UI thread.