Cashew: implement backend usage API

src/device.h

 // Copyright (c) 2010 The Chromium OS 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 SRC_DEVICE_H_
 #define SRC_DEVICE_H_
 
 #include <string>
 
 #include <base/basictypes.h>  // NOLINT
 #include <dbus-c++/dbus.h>  // NOLINT
 
 #include "src/flimflam_device_client_glue.h"
 
 namespace cashew {
 
+class Service;
+
 // represents a cellular device and monitors Flimflam state for that device
 class Device : public org::chromium::flimflam::Device_proxy,
                public DBus::IntrospectableProxy,
                public DBus::ObjectProxy {
   public:
-    Device(DBus::Connection& connection, const DBus::Path& path);  // NOLINT
+    Device(Service * const parent, DBus::Connection& connection,  // NOLINT
+           const DBus::Path& path);
     virtual ~Device();
 
     // get D-Bus path for this device
     virtual const DBus::Path& GetPath() const;
 
     // valid type values for this device
     typedef enum {
       kTypeUnknown = 0,
       kTypeEthernet,
       kTypeWifi,
       kTypeWimax,
       kTypeBluetooth,
       kTypeGPS,
       kTypeCellular,
       kTypeVendor,
     } Type;
 
     // get type for this device
     // NOTE: for now, should always be kTypeCellular
     virtual Type GetType() const;
 
-    static const char* kCarrierUnknown;
+    static const char *kCarrierUnknown;
 
     // get cellular carrier for this device
     // returns kCarrierUnknown if we don't know
     virtual const std::string& GetCarrier() const;
 
     // Flimflam Device D-Bus Proxy methods
     virtual void PropertyChanged(const std::string& property_name,
                                  const DBus::Variant& new_value);
 
   private:
+    // back pointer to our parent Service
+    Service * const parent_;
+
     // D-Bus path for Flimflam device that we represent
     // this is our unique identifier
     const DBus::Path path_;
 
     // device type
     Type type_;
 
     // cellular carrier
     std::string carrier_;
 
     // convert type string to Type enum value
     Type TypeFromString(const std::string& type) const;
 
     // we've received updated Cellular.Carrier info from Flimflam
     void OnCarrierUpdate(const std::string& carrier);
 
     // we've received updated Type info from Flimflam
     void OnTypeUpdate(const std::string& type);
 
     // get device properties from Flimflam
     void GetDeviceProperties();
 
     DISALLOW_COPY_AND_ASSIGN(Device);
 };
 
 }  // namespace cashew
 
 #endif  // SRC_DEVICE_H_