Update SoundSettings to extend DashboardFragment.

- initial round of refactoring SoundSettings to use DashboardFragment.
- add controller for Cast, Do not disturb, Alarm volume, Media volume,
  Ring volume and Notification volume.

Bug: 32276590
Test: make RunSettingsRoboTests
Change-Id: I5c02a344bff5117bfce93d7ccac650fccc82d2b0

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

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2016 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.notification;
+
+import android.content.Context;
+import android.media.AudioManager;
+import com.android.settings.core.lifecycle.Lifecycle;
+import com.android.settings.notification.VolumeSeekBarPreference.Callback;
+
+public class MediaVolumePreferenceController extends
+    VolumeSeekBarPreferenceController {
+
+    private static final String KEY_MEDIA_VOLUME = "media_volume";
+
+    public MediaVolumePreferenceController(Context context, Callback callback, Lifecycle lifecycle) {
+        super(context, callback, lifecycle);
+    }
+
+    @Override
+    public boolean isAvailable() {
+        return true;
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return KEY_MEDIA_VOLUME;
+    }
+
+    @Override
+    public int getAudioStream() {
+        return AudioManager.STREAM_MUSIC;
+    }
+
+    @Override
+    public int getMuteIcon() {
+        return com.android.internal.R.drawable.ic_audio_media_mute;
+    }
+
+}