Cleanup to screensaver settings for O

Reworked the way screensaver settings are laid out for O. Instead of
using the options menu and dialogs to navigate screensaver options,
there are now two rows: one row for the screensaver choice and
optionally its own settings, and one row for the "when to show" setting.
And now there's a nice obvious button you can press to preview your
choices.

Test: 'export ROBOTEST_FILTER="RadioButtonListFragmentTest";\
mmm -j20 packages/apps/Settings/tests/robotests'

Bug: 35031991
Change-Id: Ie7d2055fb45f6dfe72e34cb9598d9a25f7bee75a

tests/robotests/src/com/android/settings/dream/StartNowPreferenceControllerTest.java

@@ -0,0 +1,94 @@
+/*
+ * 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.dream;
+
+import android.content.Context;
+import android.support.v7.preference.PreferenceScreen;
+import android.view.View.OnClickListener;
+import android.widget.Button;
+import com.android.settings.R;
+import com.android.settings.SettingsRobolectricTestRunner;
+import com.android.settings.TestConfig;
+import com.android.settings.applications.LayoutPreference;
+import com.android.settingslib.dream.DreamBackend;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Answers;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.annotation.Config;
+import org.robolectric.util.ReflectionHelpers;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@RunWith(SettingsRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class StartNowPreferenceControllerTest {
+    private StartNowPreferenceController mController;
+    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+    private Context mContext;
+    @Mock
+    private PreferenceScreen mScreen;
+    @Mock
+    private LayoutPreference mLayoutPref;
+    @Mock
+    private Button mButton;
+    @Mock
+    private DreamBackend mBackend;
+
+
+    @Before
+    public void setup() {
+        MockitoAnnotations.initMocks(this);
+
+        mController = new StartNowPreferenceController(mContext);
+        when(mScreen.findPreference(mController.getPreferenceKey())).thenReturn(mLayoutPref);
+        when(mLayoutPref.findViewById(R.id.dream_start_now_button)).thenReturn(mButton);
+
+        ReflectionHelpers.setField(mController, "mBackend", mBackend);
+    }
+
+    @Test
+    public void setsOnClickListenerForStartNow() {
+        ArgumentCaptor<OnClickListener> captor =
+                ArgumentCaptor.forClass(Button.OnClickListener.class);
+
+        mController.displayPreference(mScreen);
+        verify(mButton).setOnClickListener(captor.capture());
+        assertThat(captor.getValue()).isNotNull();
+    }
+
+    @Test
+    public void buttonIsDisabledWhenNeverDreaming() {
+        when(mBackend.getWhenToDreamSetting()).thenReturn(DreamBackend.NEVER);
+
+        mController.updateState(mLayoutPref);
+        verify(mButton).setEnabled(false);
+    }
+
+    @Test
+    public void buttonIsEnabledWhenDreamIsAvailable() {
+        when(mBackend.getWhenToDreamSetting()).thenReturn(DreamBackend.EITHER);
+
+        mController.updateState(mLayoutPref);
+        verify(mButton).setEnabled(true);
+    }
+}