More descriptive summary for "Sleep Mode" pref.

It will either show "Off" or the name of the selected dream.

Also, move "When to sleep" out onto the visible part of the
action bar if there's room, making it much easier to discover.

Bug: 7320701
Change-Id: I1d4e2c17b764b8ee054dbb17c23f559d735e3450

src/com/android/settings/DisplaySettings.java

@@ -284,11 +284,10 @@ public class DisplaySettings extends SettingsPreferenceFragment implements
     }
 
     private void updateScreenSaverSummary() {
-        int summaryResId = DreamSettings.getSummaryResource(getActivity());
-        if (summaryResId > 0)
-            mScreenSaverPreference.setSummary(summaryResId);
-        else
-            mScreenSaverPreference.setSummary("");
+        if (mScreenSaverPreference != null) {
+            mScreenSaverPreference.setSummary(
+                    DreamSettings.getSummaryTextWithDreamName(getActivity()));
+        }
     }
 
     private void updateWifiDisplaySummary() {