ash: Add SessionController/Client mojo interfaces

ash/common/session/session_controller.h

Index: ash/common/session/session_controller.h
diff --git a/ash/common/session/session_controller.h b/ash/common/session/session_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..d8a08d7b8260224596c35d77adcebf1c0676573f
--- /dev/null
+++ b/ash/common/session/session_controller.h
@@ -0,0 +1,124 @@
+// Copyright 2016 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 ASH_COMMON_SESSION_SESSION_CONTROLLER_H_
+#define ASH_COMMON_SESSION_SESSION_CONTROLLER_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "ash/ash_export.h"
+#include "ash/public/cpp/session_types.h"
+#include "ash/public/interfaces/session_controller.mojom.h"
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+
+class AccountId;
+
+namespace ash {
+
+class SessionStateObserver;
+
+// Implements mojom::SessionController to cache session related info such as
+// session state, meta data about user sessions to support synchronous
+// queries for ash. It is targeted as a replacement for SessionStateDelegate.
+class ASH_EXPORT SessionController
+    : NON_EXPORTED_BASE(public mojom::SessionController) {
+ public:
+  SessionController();
+  ~SessionController() override;
+
+  // Binds the mojom::SessionControllerRequest to this object.
+  void BindRequest(mojom::SessionControllerRequest request);
+
+  // Returns the maximum possible number of logged in users.
+  int GetMaximumNumberOfLoggedInUsers() const;
+
+  // Returns the number of signed in users. If 0 is returned, there is either
+  // no session in progress or no active user.
+  int NumberOfLoggedInUsers() const;
+
+  // Gets the policy of adding a user session to ash.
+  AddUserSessionPolicy GetAddUserPolicy() const;
+
+  // Returns |true| if the session has been fully started for the active user.
+  // When a user becomes active, the profile and browser UI are not immediately
+  // available. Only once this method starts returning |true| is the browser
+  // startup complete and both profile and UI are fully available.
+  bool IsActiveUserSessionStarted() const;
+
+  // Returns true if the screen can be locked.
+  bool CanLockScreen() const;
+
+  // Returns true if the screen is currently locked.
+  bool IsScreenLocked() const;
+
+  // Returns true if the screen should be locked automatically when the screen
+  // is turned off or the system is suspended.
+  bool ShouldLockScreenAutomatically() const;
+
+  // Returns |true| if user session blocked by some overlying UI. It can be
+  // login screen, lock screen or screen for adding users into multi-profile
+  // session.
+  bool IsUserSessionBlocked() const;
+
+  // Gets the ash session state.
+  session_manager::SessionState GetSessionState() const;
+
+  // Gets the user sessions.

[James Cook, 2016/12/06 18:08:24]

nit: Document the order (arbitrary or current user first?)

[xiyuan, 2016/12/06 19:24:21]

Done.

+  const std::vector<mojom::UserSessionPtr>& GetUserSessions() const;
+
+  // Locks the screen. The locking happens asynchronously.
+  void LockScreen();
+
+  // Switches to another active user with |account_id| (if that user has
+  // already signed in).
+  void SwitchActiveUser(const AccountId& account_id);
+
+  // Switches the active user to the next or previous user, with the same
+  // ordering as user sessions are created.
+  void CycleActiveUser(bool next_user);
+
+  void AddSessionStateObserver(SessionStateObserver* observer);
+  void RemoveSessionStateObserver(SessionStateObserver* observer);
+
+  // mojom::SessionController
+  void SetClient(mojom::SessionControllerClientPtr client) override;
+  void SetSessionInfo(mojom::SessionInfoPtr info) override;
+  void UpdateUserSession(mojom::UserSessionPtr user_session) override;
+  void SetUserSessionOrder(
+      const std::vector<uint32_t>& user_session_order) override;
+
+ private:
+  void SetSessionState(session_manager::SessionState state);
+  void AddUserSession(mojom::UserSessionPtr user_session);
+
+  // Bindings for mojom::SessionController interface.
+  mojo::BindingSet<mojom::SessionController> bindings_;
+
+  // Client interface to session manager code (chrome).
+  mojom::SessionControllerClientPtr client_;
+
+  // Cached session info.
+  uint32_t max_users_ = 0u;
+  bool can_lock_ = false;
+  bool should_lock_screen_automatically_ = false;
+  AddUserSessionPolicy add_user_session_policy_ = AddUserSessionPolicy::ALLOWED;
+  session_manager::SessionState state_ = session_manager::SessionState::UNKNOWN;
+
+  // Cached user session info sorted by the order from SetUserSessionOrder.
+  std::vector<mojom::UserSessionPtr> user_sessions_;
+
+  base::ObserverList<ash::SessionStateObserver> observers_;
+
+  uint32_t active_session_id_ = 0u;

[James Cook, 2016/12/06 18:08:25]

nit: document, since we have lots of uint32s and lots of types of ids. :-)

[xiyuan, 2016/12/06 19:24:21]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(SessionController);
+};
+
+}  // namespace ash
+
+#endif  // ASH_COMMON_SESSION_SESSION_CONTROLLER_H_