apmanager: support for WiFi devices and interfaces

Added DeviceInfo for enumerating WiFi devices (PHYs) and detecting
WiFi interfaces. Also Created a Device class for abstracting WiFi PHYs,
which will maintain the device's capabilities and manage interfaces
created on the device.

Integrate Device with Manager and Config to allow user to start
an AP service without providing interface information.

Next up, will focus on parsing HT/VHT capabilities for each band and
integrate it into ap configuration. Also adding shill support for
claim/release interface.

BUG=chromium:431763
TEST=unittest

Change-Id: I62f4251064483b57e264d1278fde68022a737aea
Reviewed-on: https://chromium-review.googlesource.com/231257
Reviewed-by: Peter Qiu <zqiu@chromium.org>
Commit-Queue: Peter Qiu <zqiu@chromium.org>
Tested-by: Peter Qiu <zqiu@chromium.org>
diff --git a/service.h b/service.h
index f7c04b9..feb2ceb 100644
--- a/service.h
+++ b/service.h
@@ -10,16 +10,17 @@
 #include <base/macros.h>
 #include <chromeos/process.h>
 
+#include "apmanager/config.h"
 #include "apmanager/dbus_adaptors/org.chromium.apmanager.Service.h"
 
 namespace apmanager {
 
-class Config;
+class Manager;
 
 class Service : public org::chromium::apmanager::ServiceAdaptor,
                 public org::chromium::apmanager::ServiceInterface {
  public:
-  explicit Service(int service_identifier);
+  Service(Manager* manager, int service_identifier);
   virtual ~Service();
 
   // Implementation of ServiceInterface.
@@ -52,6 +53,7 @@
   // a SIGKILL if failed to terminated with SIGTERM.
   void StopHostapdProcess();
 
+  Manager* manager_;
   int service_identifier_;
   std::string service_path_;
   dbus::ObjectPath dbus_path_;