Add an developer option to enable config_navBarDefaultTransparent

This enables the user to make navigation bar color transparent by
default. It will only affect apps which don't specify the navigation
bar color.

Fix: 232195501
Test: atest TransparentNavigationBarPreferenceControllerTest
Change-Id: I91581558b92abeaa3501b9749f1a1ab43db8e771

tests/robotests/src/com/android/settings/development/TransparentNavigationBarPreferenceControllerTest.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2023 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;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import androidx.preference.PreferenceScreen;
+import androidx.preference.SwitchPreference;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+@RunWith(RobolectricTestRunner.class)
+public class TransparentNavigationBarPreferenceControllerTest {
+
+    @Mock
+    private PreferenceScreen mScreen;
+    @Mock
+    private SwitchPreference mPreference;
+
+    private TransparentNavigationBarPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mController = new TransparentNavigationBarPreferenceController(
+                RuntimeEnvironment.application) {
+            private boolean mEnabled;
+
+            protected boolean isEnabled() {
+                return mEnabled;
+            }
+
+            protected void setEnabled(boolean enabled) {
+                mEnabled = enabled;
+            }
+        };
+        when(mScreen.findPreference(mController.getPreferenceKey())).thenReturn(mPreference);
+        mController.displayPreference(mScreen);
+    }
+
+    @Test
+    public void updateState_enabled_shouldCheckedPreference() {
+        mController.setEnabled(true);
+        mController.updateState(mPreference);
+
+        verify(mPreference).setChecked(true);
+    }
+
+    @Test
+    public void updateState_disabled_shouldUncheckedPreference() {
+        mController.setEnabled(false);
+        mController.updateState(mPreference);
+
+        verify(mPreference).setChecked(false);
+    }
+
+    @Test
+    public void onPreferenceChange_preferenceChecked_shouldBeEnabled() {
+        mController.onPreferenceChange(mPreference, true /* new value */);
+
+        assertTrue(mController.isEnabled());
+    }
+
+    @Test
+    public void onPreferenceChange__preferenceUnchecked_shouldNotBeEnabled() {
+        mController.onPreferenceChange(mPreference, false /* new value */);
+
+        assertFalse(mController.isEnabled());
+    }
+
+    @Test
+    public void onDeveloperOptionsSwitchDisabled_preferenceShouldNotBeEnabled() {
+        mController.onDeveloperOptionsSwitchDisabled();
+
+        assertFalse(mController.isEnabled());
+        verify(mPreference).setEnabled(false);
+        verify(mPreference).setChecked(false);
+    }
+}