Add remote volume slider conditionally.

Issue before this CL:
RemoteVolumePreferenceController only return available when
it is casting, otherwise return CONDITIONALLY_UNAVAILABLE.
However slice database only index available controllers and keep
this cache. So remote slider won't be indexed if it is not casting
at that time.

As a tmp fix, this CL make controller always return available
unsearchable to make it indexed by database. However only add
that slice if it is casting.

Bug: 130124950
Test: RunSettingsRoboTests
Change-Id: I191144844d6ba7ccbe3dc1c9d19801adb978abc6

src/com/android/settings/notification/RemoteVolumePreferenceController.java

@@ -43,7 +43,6 @@ public class RemoteVolumePreferenceController extends VolumeSeekBarPreferenceCon
     @VisibleForTesting
     static final int REMOTE_VOLUME = 100;
 
-    private MediaSessionManager mMediaSessionManager;
     private MediaSessions mMediaSessions;
     @VisibleForTesting
     MediaSession.Token mActiveToken;
@@ -86,28 +85,39 @@ public class RemoteVolumePreferenceController extends VolumeSeekBarPreferenceCon
 
     public RemoteVolumePreferenceController(Context context) {
         super(context, KEY_REMOTE_VOLUME);
-        mMediaSessionManager = context.getSystemService(MediaSessionManager.class);
         mMediaSessions = new MediaSessions(context, Looper.getMainLooper(), mCallbacks);
+        updateToken(getActiveRemoteToken(mContext));
     }
 
     @Override
     public int getAvailabilityStatus() {
-        final List<MediaController> controllers = mMediaSessionManager.getActiveSessions(null);
+        // Always return true to make it indexed in database
+        return AVAILABLE_UNSEARCHABLE;
+    }
+
+    /**
+     * Return {@link android.media.session.MediaSession.Token} for active remote token, or
+     * {@code null} if there is no active remote token.
+     */
+    public static MediaSession.Token getActiveRemoteToken(Context context) {
+        final MediaSessionManager sessionManager = context.getSystemService(
+                MediaSessionManager.class);
+        final List<MediaController> controllers = sessionManager.getActiveSessions(null);
         for (MediaController mediaController : controllers) {
             final MediaController.PlaybackInfo pi = mediaController.getPlaybackInfo();
             if (isRemote(pi)) {
-                updateToken(mediaController.getSessionToken());
+                return mediaController.getSessionToken();
-                return AVAILABLE;
             }
         }
 
         // No active remote media at this point
-        return CONDITIONALLY_UNAVAILABLE;
+        return null;
     }
 
     @Override
     public void displayPreference(PreferenceScreen screen) {
         super.displayPreference(screen);
+        mPreference.setVisible(mActiveToken != null);
         if (mMediaController != null) {
             updatePreference(mPreference, mActiveToken, mMediaController.getPlaybackInfo());
         }

src/com/android/settings/panel/VolumePanel.java

@@ -30,6 +30,7 @@ import android.net.Uri;
 import android.provider.Settings;
 
 import com.android.settings.R;
+import com.android.settings.notification.RemoteVolumePreferenceController;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -54,7 +55,9 @@ public class VolumePanel implements PanelContent {
     @Override
     public List<Uri> getSlices() {
         final List<Uri> uris = new ArrayList<>();
+        if (RemoteVolumePreferenceController.getActiveRemoteToken(mContext) != null) {
             uris.add(VOLUME_REMOTE_MEDIA_URI);
+        }
         uris.add(VOLUME_MEDIA_URI);
         uris.add(MEDIA_OUTPUT_INDICATOR_SLICE_URI);
         uris.add(VOLUME_CALL_URI);

tests/robotests/src/com/android/settings/notification/RemoteVolumePreferenceControllerTest.java

@@ -29,10 +29,12 @@ import android.media.session.MediaSession;
 import android.media.session.MediaSessionManager;
 
 import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
 
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Answers;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.robolectric.RobolectricTestRunner;
@@ -50,9 +52,9 @@ public class RemoteVolumePreferenceControllerTest {
     private MediaSessionManager mMediaSessionManager;
     @Mock
     private MediaController mMediaController;
-    @Mock
+    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private ISessionController mStub;
-    @Mock
+    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private ISessionController mStub2;
     private MediaSession.Token mToken;
     private MediaSession.Token mToken2;
@@ -78,22 +80,30 @@ public class RemoteVolumePreferenceControllerTest {
         mPlaybackInfo = new MediaController.PlaybackInfo(
                 MediaController.PlaybackInfo.PLAYBACK_TYPE_REMOTE, 0, MAX_POS, CURRENT_POS, null);
         when(mMediaController.getPlaybackInfo()).thenReturn(mPlaybackInfo);
+        when(mMediaController.getSessionToken()).thenReturn(mToken);
     }
 
     @Test
-    public void isAvailable_containRemoteMedia_returnTrue() {
+    public void getActiveRemoteToken_containRemoteMedia_returnToken() {
         when(mMediaController.getPlaybackInfo()).thenReturn(
                 new MediaController.PlaybackInfo(MediaController.PlaybackInfo.PLAYBACK_TYPE_REMOTE,
                         0, 0, 0, null));
-        assertThat(mController.isAvailable()).isTrue();
+        assertThat(mController.getActiveRemoteToken(mContext)).isEqualTo(mToken);
     }
 
     @Test
-    public void isAvailable_noRemoteMedia_returnFalse() {
+    public void getActiveRemoteToken_noRemoteMedia_returnNull() {
         when(mMediaController.getPlaybackInfo()).thenReturn(
                 new MediaController.PlaybackInfo(MediaController.PlaybackInfo.PLAYBACK_TYPE_LOCAL,
                         0, 0, 0, null));
-        assertThat(mController.isAvailable()).isFalse();
+        assertThat(mController.getActiveRemoteToken(mContext)).isNull();
+    }
+
+    @Test
+    public void isAvailable_returnAvailableUnsearchable() {
+        assertThat(mController.isAvailable()).isTrue();
+        assertThat(mController.getAvailabilityStatus()).isEqualTo(
+                BasePreferenceController.AVAILABLE_UNSEARCHABLE);
     }
 
     @Test