Support transition between chrome and user mode console

chromeos/dbus/console_service_client.h

+// Copyright 2014 The Chromium 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 CHROMEOS_DBUS_CONSOLE_SERVICE_CLIENT_H_
+#define CHROMEOS_DBUS_CONSOLE_SERVICE_CLIENT_H_
+
+#include "base/observer_list.h"
+#include "chromeos/chromeos_export.h"
+#include "chromeos/dbus/dbus_client.h"
+
+namespace chromeos {
+
+class CHROMEOS_EXPORT ConsoleServiceClient : public DBusClient {

[Daniel Erat, 2014/10/31 18:15:02]

should this be named ConsoleServiceProvider?

i thought that all of the other classes in this directory are named "Client"
because they're clients of system daemons running on chrome os. this class
doesn't appear to do that; it offers a service for other processes to call. it
seems much more similar to the classes in chrome/browser/chromeos/dbus than the
ones in chromeos/dbus.

i think that the right approach is probably to move
c/b/chromeos/dbus/cros_dbus_service.h to chromeos/dbus and then make this class
derive from it instead of from DBusClient.

[dsodman, 2014/10/31 18:43:25]

I think that is a much bigger change than what I'm trying to do with the
console.  I would prefer to get this submitted to unblock testing, and then do a
separate follow-on change investigates what it would take to move
c/b/chromeos/dbus/cros_dbus_service.h to chromeos/dbus and make the console a
proper "client"

+ public:
+  class Observer {
+   public:
+    virtual void OnActivateConsole(int console_id) = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+  virtual bool HasObserver(Observer* observer) = 0;
+
+  static ConsoleServiceClient* Create();
+  static ConsoleServiceClient* GetInstance();
+  virtual ~ConsoleServiceClient() override;
+
+ protected:
+  ConsoleServiceClient();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ConsoleServiceClient);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_DBUS_CROS_CONSOLE_SERVICE_CLIENT_H_