Add support for visualizing secondary users.

This functionality adds the secondary users to the screen, but
currently does not populate the information for them. Once the
external stats query works, I will add a loader which will
populate this information.

This also does not cover work profiles. Support for that is
forthcoming.

Bug: 34715777, 34225103
Test: Settings Robotest
Change-Id: Ib9b692b214f5ce5d303dfd64516381443d4acebd

src/com/android/settings/deviceinfo/storage/SecondaryUserController.java

@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.deviceinfo.storage;
+
+import android.content.Context;
+import android.content.pm.UserInfo;
+import android.os.UserManager;
+import android.support.annotation.VisibleForTesting;
+import android.support.v7.preference.PreferenceGroup;
+import android.support.v7.preference.PreferenceScreen;
+
+import com.android.settings.Utils;
+import com.android.settings.applications.UserManagerWrapper;
+import com.android.settings.core.PreferenceController;
+
+import java.util.List;
+
+/**
+ * SecondaryUserController controls the preferences on the Storage screen which had to do with
+ * secondary users.
+ */
+public class SecondaryUserController extends PreferenceController {
+    // PreferenceGroupKey to try to add our preference onto.
+    private static final String TARGET_PREFERENCE_GROUP_KEY = "pref_secondary_users";
+    private static final String PREFERENCE_KEY_BASE = "pref_user_";
+
+    private UserInfo mUser;
+    private StorageItemPreferenceAlternate mPreference;
+
+    /**
+     * Adds the appropriate controllers to a controller list for handling all secondary users on
+     * a device.
+     * @param context Context for initializing the preference controllers.
+     * @param controllers List of preference controllers for a Settings fragment.
+     */
+    public static void addAllSecondaryUserControllers(Context context,
+            UserManagerWrapper userManager, List<PreferenceController> controllers) {
+        UserInfo primaryUser = userManager.getPrimaryUser();
+        boolean addedUser = false;
+        List<UserInfo> infos = userManager.getUsers();
+        for (int i = 0, size = infos.size(); i < size; i++) {
+            UserInfo info = infos.get(i);
+            if (Utils.isProfileOf(primaryUser, info)) {
+                continue;
+            }
+
+            controllers.add(new SecondaryUserController(context, info));
+            addedUser = true;
+        }
+
+        if (!addedUser) {
+            controllers.add(new NoSecondaryUserController(context));
+        }
+    }
+
+    /**
+     * Constructor for a given secondary user.
+     * @param context Context to initialize the underlying {@link PreferenceController}.
+     * @param info {@link UserInfo} for the secondary user which this controllers covers.
+     */
+    @VisibleForTesting
+    SecondaryUserController(Context context, UserInfo info) {
+        super(context);
+        mUser = info;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        if (mPreference == null) {
+            mPreference = new StorageItemPreferenceAlternate(mContext);
+
+            PreferenceGroup group =
+                    (PreferenceGroup) screen.findPreference(TARGET_PREFERENCE_GROUP_KEY);
+            mPreference.setTitle(mUser.name);
+            mPreference.setKey(PREFERENCE_KEY_BASE + mUser.id);
+            group.setVisible(true);
+            group.addPreference(mPreference);
+        }
+    }
+
+    @Override
+    public boolean isAvailable() {
+        return true;
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return (mPreference != null) ? mPreference.getKey() : null;
+    }
+
+    /**
+     * Sets the size for the preference.
+     * @param size Size in bytes.
+     */
+    public void setSize(long size) {
+        if (mPreference != null) {
+            mPreference.setStorageSize(size);
+        }
+    }
+
+    private static class NoSecondaryUserController extends PreferenceController {
+        public NoSecondaryUserController(Context context) {
+            super(context);
+        }
+
+        @Override
+        public void displayPreference(PreferenceScreen screen) {
+            PreferenceGroup group =
+                    (PreferenceGroup) screen.findPreference(TARGET_PREFERENCE_GROUP_KEY);
+            if (group == null) {
+                return;
+            }
+            screen.removePreference(group);
+        }
+
+        @Override
+        public boolean isAvailable() {
+            return true;
+        }
+
+        @Override
+        public String getPreferenceKey() {
+            return null;
+        }
+
+    }
+}