Volume slider content description

Volume, ring and acessibility sliders now report their names
when talk back is on.

Examples:
26% acessibility seek control, use volume keys to adjust.
0% ring seek control, disabled.

Change-Id: I0a775a9b90254c9f338b9f4f38efbff10f626853
Fixes: 62354047
Test: Turn talk back on, tap on volume sliders

packages/SystemUI/src/com/android/systemui/volume/VolumeDialogImpl.java

@@ -761,6 +761,7 @@ public class VolumeDialogImpl implements VolumeDialog, TunerService.Tunable {
 
         // update header text
         Util.setText(row.header, getStreamLabelH(ss));
+        row.slider.setContentDescription(row.header.getText());
         mConfigurableTexts.add(row.header, ss.name);
 
         // update icon