Introduce controller for transcode notifications

This is to provider users with control over whether to show transcoding
notifications or not.

By default we show the notifications.

The controller resides within the Media transcoding settings under
Developer Options.

BUG: 170973510
Test: manual. unit test added.
Change-Id: I7172f583ce4c1a53e5d5ccc07625f201852db43a

res/xml/transcode_settings.xml

@@ -35,4 +35,9 @@
         android:key="transcode_default"
         android:title="@string/transcode_default"
         settings:controller="com.android.settings.development.transcode.TranscodeDefaultOptionPreferenceController" />
+
+    <SwitchPreference
+        android:key="transcode_notification"
+        android:title="@string/transcode_notification"
+        settings:controller="com.android.settings.development.transcode.TranscodeNotificationPreferenceController" />
 </PreferenceScreen>

src/com/android/settings/development/transcode/TranscodeNotificationPreferenceController.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2021 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.development.transcode;
+
+import android.content.Context;
+import android.os.SystemProperties;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.settings.core.TogglePreferenceController;
+
+/**
+ * The controller (in the Media transcoding settings) indicating the user's preference to show
+ * or hide the transcoding notifications.
+ */
+public class TranscodeNotificationPreferenceController extends TogglePreferenceController {
+    @VisibleForTesting
+    static final String TRANSCODE_NOTIFICATION_SYS_PROP_KEY =
+            "persist.sys.fuse.transcode_notification";
+
+    public TranscodeNotificationPreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public boolean isChecked() {
+        return SystemProperties.getBoolean(TRANSCODE_NOTIFICATION_SYS_PROP_KEY, true);
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        SystemProperties.set(TRANSCODE_NOTIFICATION_SYS_PROP_KEY, String.valueOf(isChecked));
+        return true;
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+}

tests/unit/src/com/android/settings/development/transcode/TranscodeNotificationPreferenceControllerTest.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2021 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.development.transcode;
+
+import static com.android.settings.development.transcode.TranscodeNotificationPreferenceController.TRANSCODE_NOTIFICATION_SYS_PROP_KEY;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.os.SystemProperties;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import com.android.settings.core.BasePreferenceController;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class TranscodeNotificationPreferenceControllerTest {
+    private TranscodeNotificationPreferenceController mUnderTest;
+
+    @Before
+    public void setUp() {
+        Context context = ApplicationProvider.getApplicationContext();
+        mUnderTest = new TranscodeNotificationPreferenceController(context, "notification_key");
+    }
+
+    @Test
+    public void isChecked_whenSysPropSet_shouldReturnTrue() {
+        SystemProperties.set(TRANSCODE_NOTIFICATION_SYS_PROP_KEY, "true");
+        assertThat(mUnderTest.isChecked()).isTrue();
+    }
+
+    @Test
+    public void isChecked_whenSysPropUnset_shouldReturnFalse() {
+        SystemProperties.set(TRANSCODE_NOTIFICATION_SYS_PROP_KEY, "false");
+        assertThat(mUnderTest.isChecked()).isFalse();
+    }
+
+    @Test
+    public void setChecked_withTrue_shouldSetSysProp() {
+        mUnderTest.setChecked(true);
+        assertThat(
+                SystemProperties.getBoolean(TRANSCODE_NOTIFICATION_SYS_PROP_KEY, false)).isTrue();
+    }
+
+    @Test
+    public void setChecked_withFalse_shouldUnsetSysProp() {
+        mUnderTest.setChecked(false);
+        assertThat(
+                SystemProperties.getBoolean(TRANSCODE_NOTIFICATION_SYS_PROP_KEY, true)).isFalse();
+    }
+
+    @Test
+    public void getAvailabilityStatus_shouldReturn_isAvailable() {
+        assertThat(mUnderTest.getAvailabilityStatus()).isEqualTo(
+                BasePreferenceController.AVAILABLE);
+    }
+}