Introduced UserController for multi-user functionality

The new helper class encapsulates user life-cycle management, provided by
ActivityManagerService.

Bug: 24745840
Change-Id: I8ebfa38febc4090390d1c45a9fc47398e52693ae
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 54ac58a..99f7ec6 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -97,7 +97,6 @@
 import android.service.voice.IVoiceInteractionSession;
 import android.util.ArrayMap;
 import android.util.ArraySet;
-import android.util.DisplayMetrics;
 import android.util.EventLog;
 import android.util.Slog;
 import android.util.SparseArray;
@@ -2693,7 +2692,7 @@
             // Complete user switch
             if (startingUsers != null) {
                 for (int i = 0; i < startingUsers.size(); i++) {
-                    mService.finishUserSwitch(startingUsers.get(i));
+                    mService.mUserController.finishUserSwitch(startingUsers.get(i));
                 }
             }
             // Complete starting up of background users
@@ -2701,7 +2700,7 @@
                 startingUsers = new ArrayList<UserState>(mStartingBackgroundUsers);
                 mStartingBackgroundUsers.clear();
                 for (int i = 0; i < startingUsers.size(); i++) {
-                    mService.finishUserBoot(startingUsers.get(i));
+                    mService.mUserController.finishUserBoot(startingUsers.get(i));
                 }
             }
         }
@@ -3756,10 +3755,7 @@
     /** Checks whether the userid is a profile of the current user. */
     boolean isCurrentProfileLocked(int userId) {
         if (userId == mCurrentUser) return true;
-        for (int i = 0; i < mService.mCurrentProfileIds.length; i++) {
-            if (mService.mCurrentProfileIds[i] == userId) return true;
-        }
-        return false;
+        return mService.mUserController.isCurrentProfileLocked(userId);
     }
 
     /** Checks whether the activity should be shown for current user. */