shill: Support Cellular CDMA activation.

Still TODO is communicating the activation error codes to the Cellular service.
... And, of course, asynchronous calls throughout.

BUG=chromium-os:19305
TEST=unit tests

Change-Id: I3e0b4a5a8d3c4c74db35ce7f74b5d958677d8b66
Reviewed-on: http://gerrit.chromium.org/gerrit/6192
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Chris Masone <cmasone@chromium.org>
diff --git a/cellular_service.h b/cellular_service.h
index 1c75358..a16b1bb 100644
--- a/cellular_service.h
+++ b/cellular_service.h
@@ -27,8 +27,15 @@
                   const CellularRefPtr &device);
   virtual ~CellularService();
 
+  // Inherited from Service.
   virtual void Connect();
   virtual void Disconnect();
+  virtual void ActivateCellularModem(const std::string &carrier);
+
+  const std::string &activation_state() const { return activation_state_; }
+  void set_activation_state(const std::string &state) {
+    activation_state_ = state;
+  }
 
   uint8 strength() const { return strength_; }
   void set_strength(uint8 strength) { strength_ = strength; }