Replace dynamic summary text for SettingPref

All SettingPrefs that have dynamic summaries are replaced
by placeholder text. Changes are for:
- Battery Saver "Turn on automatically"
- Notification "Dock speaker plays"
- Notification "Emergency tone"

Bug: 36101902
Test: make RunSettingsRoboTests
Change-Id: Ic2556055c155989015dbef6b507d3e3b45b779b5

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

@@ -121,6 +121,19 @@ public class SettingPref {
         if (mTwoState != null) {
             mTwoState.setChecked(val != 0);
         } else if (mDropDown != null) {
+            if (mValues != null) {
+                int index = 0;
+                for (int len = mValues.length; index < len; index++) {
+                    if (mValues[index] == val) {
+                        break;
+                    }
+                }
+
+                if (index < mValues.length) {
+                    CharSequence entry = mDropDown.getEntries()[index];
+                    mDropDown.setSummary(entry);
+                }
+            }
             mDropDown.setValue(Integer.toString(val));
         }
     }