Implement a dbus client for CupsTool.

chromeos/dbus/debug_daemon_client.h

Index: chromeos/dbus/debug_daemon_client.h
diff --git a/chromeos/dbus/debug_daemon_client.h b/chromeos/dbus/debug_daemon_client.h
index af32bdc4ce0617594d7178bdda8a9aef2e42a70e..b9810cf0fb97f8209a6a5afa3e0de6a56436df9a 100644
--- a/chromeos/dbus/debug_daemon_client.h
+++ b/chromeos/dbus/debug_daemon_client.h
@@ -209,6 +209,29 @@ class CHROMEOS_EXPORT DebugDaemonClient
       const std::map<pid_t, int32_t>& pid_to_oom_score_adj,
       const SetOomScoreAdjCallback& callback) = 0;
 
+  // A callback to handle the result of AddPrinter.

[hashimoto, 2016/09/12 05:20:36]

nit: "the result of CupsAddPrinter."

[skau, 2016/09/12 17:53:56]

Done.

+  using AddPrinterCallback = base::Callback<void(bool success)>;

[hashimoto, 2016/09/12 05:20:36]

nit: CupsAddPrinterCallback should be more intuitive?

[skau, 2016/09/12 17:53:56]

Done.

+
+  // Calls CupsAddPrinter.  |name| is the printer name. |uri| is the device
+  // uri. |ppd_path| is the absolute path to the PPD file. |ipp_everywhere|
+  // is true for autoconf of IPP Everywhere printers.  |callback| is called
+  // after method success, |error_callback| otherwise.

[hashimoto, 2016/09/12 05:20:36]

nit: In "|callback| is called after method success", IIUC "success" means that
the D-Bus method call is properly done (i.e. the method call is sent to the
debugd, and the response for it is received).
OTOH the "success" parameter of the callback means if any error happened in
debugd when doing the actual printer-related work to respond to the D-Bus method
call.

Also, |error_callback| will be called if an error occurs at D-Bus protocol
level, but it won't be called when an error occurs when debugd fails to do the
actual printer-related work.

Please make this distinction clear.

[skau, 2016/09/12 17:53:56]

Done.

+  virtual void CupsAddPrinter(const std::string& name,
+                              const std::string& uri,
+                              const std::string& ppd_path,
+                              bool ipp_everywhere,
+                              const AddPrinterCallback& callback,
+                              const base::Closure& error_callback) = 0;
+
+  // A callback to handle the result of RemovePrinter.

[hashimoto, 2016/09/12 05:20:36]

ditto.

[skau, 2016/09/12 17:53:56]

Done.

+  using RemovePrinterCallback = base::Callback<void(bool success)>;

[hashimoto, 2016/09/12 05:20:36]

ditto.

[skau, 2016/09/12 17:53:56]

Done.

+
+  // Calls CupsRemovePrinter.  |name| is the printer name as registered in
+  // CUPS.  |callback| is called on success, |error_callback| otherwise.

[hashimoto, 2016/09/12 05:20:36]

ditto.

[skau, 2016/09/12 17:53:56]

Done.

+  virtual void CupsRemovePrinter(const std::string& name,
+                                 const RemovePrinterCallback& callback,
+                                 const base::Closure& error_callback) = 0;
+
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via DBusThreadManager::Get().
   static DebugDaemonClient* Create();