shill_manager: add APIs for setting interface modes

This is needed to allow apmanager to setup an AP/station mode
interface when starting/stopping an AP service.

Bug: 25113165
TEST=Device setup on Brillo boards

Change-Id: I2b5b708409fe1c59e0333b1e4347d46ba0162847
diff --git a/shill_manager.h b/shill_manager.h
index dd0089b..12e9d16 100644
--- a/shill_manager.h
+++ b/shill_manager.h
@@ -40,6 +40,12 @@
   virtual void ClaimInterface(const std::string& interface_name);
   // Release the given interface |interface_name| to shill.
   virtual void ReleaseInterface(const std::string& interface_name);
+#if defined(__BRILLO__)
+  // Setup an AP mode interface.
+  virtual bool SetupApModeInterface(std::string* interface_name);
+  // Setup a station mode interface.
+  virtual bool SetupStationModeInterface(std::string* interface_name);
+#endif  // __BRILLO__
 
  private:
   void OnShillServiceAppeared();