Fix content description and accessibility focus on

PreviewSeekBarPreferenceFragment.
Bug: 27911511

Change-Id: I45673e582a29028cb0598669b0fa1a48c071181d

src/com/android/settings/PreviewPagerAdapter.java

@@ -54,9 +54,6 @@ public class PreviewPagerAdapter extends PagerAdapter {
             mPreviewFrames[i].setLayoutParams(new LinearLayout.LayoutParams(
                     LinearLayout.LayoutParams.MATCH_PARENT,
                     LinearLayout.LayoutParams.MATCH_PARENT));
-            mPreviewFrames[i].setContentDescription(
-                    context.getString(R.string.preview_page_indicator_content_description, i + 1,
-                            previewSampleResIds.length));
 
             for (Configuration configuration : configurations) {
                 // Create a new configuration for the specified value. It won't