mus: Add UserActivityMonitor.

components/mus/ws/window_server.cc

Index: components/mus/ws/window_server.cc
diff --git a/components/mus/ws/window_server.cc b/components/mus/ws/window_server.cc
index 5ee158bb43518ee6971fedf9c034ddde648e6fde..7849e149f34081666bb1403fdf6f0ed5adc0d003 100644
--- a/components/mus/ws/window_server.cc
+++ b/components/mus/ws/window_server.cc
@@ -16,6 +16,7 @@
 #include "components/mus/ws/display_manager.h"
 #include "components/mus/ws/operation.h"
 #include "components/mus/ws/server_window.h"
+#include "components/mus/ws/user_activity_monitor.h"
 #include "components/mus/ws/window_coordinate_conversions.h"
 #include "components/mus/ws/window_manager_access_policy.h"
 #include "components/mus/ws/window_manager_display_root.h"
@@ -40,7 +41,10 @@ WindowServer::WindowServer(
       current_operation_(nullptr),
       in_destructor_(false),
       next_wm_change_id_(0),
-      window_manager_window_tree_factory_set_(this, &user_id_tracker_) {}
+      window_manager_window_tree_factory_set_(this, &user_id_tracker_) {
+  user_id_tracker_.AddObserver(this);
+  OnUserIdAdded(user_id_tracker_.active_id());

[sadrul, 2016/06/27 20:46:13]

This is necessary since the 'root user id' is added upon construction of
UserIdTracker, and the observers are not notified of it.

I didn't RemoveObserver() from user_id_tracker_ from the dtor since at that
point, UserIdTracker is also being destroyed.

+}
 
 WindowServer::~WindowServer() {
   in_destructor_ = true;
@@ -232,6 +236,12 @@ void WindowServer::OnFirstWindowManagerWindowTreeFactoryReady() {
   delegate_->CreateDefaultDisplays();
 }
 
+UserActivityMonitor* WindowServer::GetUserActivityMonitorForUser(
+    const UserId& user_id) {
+  DCHECK_GT(activity_monitor_map_.count(user_id), 0u);
+  return activity_monitor_map_[user_id].get();
+}
+
 bool WindowServer::SetFocusedWindow(ServerWindow* window) {
   // TODO(sky): this should fail if there is modal dialog active and |window|
   // is outside that.
@@ -683,5 +693,16 @@ WindowManagerState* WindowServer::GetWindowManagerStateForUser(
       user_id);
 }
 
+void WindowServer::OnActiveUserIdChanged(const UserId& previously_active_id,
+                                         const UserId& active_id) {}
+
+void WindowServer::OnUserIdAdded(const UserId& id) {
+  activity_monitor_map_[id] = base::MakeUnique<UserActivityMonitor>(nullptr);
+}
+
+void WindowServer::OnUserIdRemoved(const UserId& id) {
+  activity_monitor_map_.erase(id);
+}
+
 }  // namespace ws
 }  // namespace mus