Migrate ChooseAccountActivity to DashboardFragment

- Build a controller to generate/manage a list of preferences.
- Move some logics to the controller and add tests.
- Rename to ChooseAccountFragment.

Bug: 73899467
Test: make RunSettingsRoboTests -j
      atest UniquePreferenceTest SettingsGatewayTest
Change-Id: Id2906c4b922ef159d08c803b976671264c54665f

src/com/android/settings/accounts/ProviderEntry.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2018 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.accounts;
+
+import com.android.internal.util.CharSequences;
+
+public class ProviderEntry implements Comparable<ProviderEntry> {
+    private final CharSequence name;
+    private final String type;
+
+    ProviderEntry(CharSequence providerName, String accountType) {
+        name = providerName;
+        type = accountType;
+    }
+
+    public int compareTo(ProviderEntry another) {
+        if (name == null) {
+            return -1;
+        }
+        if (another.name == null) {
+            return +1;
+        }
+        return CharSequences.compareToIgnoreCase(name, another.name);
+    }
+
+    public CharSequence getName() {
+        return name;
+    }
+
+    public String getType() {
+        return type;
+    }
+}