Track selection UI needs to scroll.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=124976833

demo/src/main/java/com/google/android/exoplayer/demo/TrackSelectionHelper.java

@@ -98,7 +98,8 @@ import java.util.Locale;
 
 
   @SuppressLint("InflateParams")
   @SuppressLint("InflateParams")
   private View buildView(LayoutInflater inflater) {
   private View buildView(LayoutInflater inflater) {
-    ViewGroup root = (ViewGroup) inflater.inflate(R.layout.track_selection_dialog, null);
+    View view = inflater.inflate(R.layout.track_selection_dialog, null);
+    ViewGroup root = (ViewGroup) view.findViewById(R.id.root);
 
 
     // View for disabling the renderer.
     // View for disabling the renderer.
     disableView = (CheckedTextView) inflater.inflate(
     disableView = (CheckedTextView) inflater.inflate(
@@ -150,7 +151,7 @@ import java.util.Locale;
     }
     }
 
 
     updateViews();
     updateViews();
-    return root;
+    return view;
   }
   }
 
 
   private void updateViews() {
   private void updateViews() {

demo/src/main/res/layout/track_selection_dialog.xml

@@ -13,7 +13,13 @@
      See the License for the specific language governing permissions and
      See the License for the specific language governing permissions and
      limitations under the License.
      limitations under the License.
 -->
 -->
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:orientation="vertical"
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="wrap_content"
     android:layout_width="wrap_content"
-    android:layout_height="wrap_content"/>
+    android:layout_height="match_parent">
+
+  <LinearLayout android:id="@+id/root"
+      android:orientation="vertical"
+      android:layout_width="wrap_content"
+      android:layout_height="wrap_content"/>
+
+</ScrollView>