Fix sort orders on longs.

The int conversion narrows a long possibly inverting its sign. This may
lead to broken comparator sort orders.
Caught by Error Prone.
Bug: 27723540

Change-Id: I53d70c25a22cdcfc496443395b170f586d259fa7

src/com/android/settings/UsageStatsActivity.java

@@ -75,14 +75,14 @@ public class UsageStatsActivity extends Activity implements OnItemSelectedListen
         @Override
         public final int compare(UsageStats a, UsageStats b) {
             // return by descending order
-            return (int)(b.getLastTimeUsed() - a.getLastTimeUsed());
+            return Long.compare(b.getLastTimeUsed(), a.getLastTimeUsed());
         }
     }
 
     public static class UsageTimeComparator implements Comparator<UsageStats> {
         @Override
         public final int compare(UsageStats a, UsageStats b) {
-            return (int)(b.getTotalTimeInForeground() - a.getTotalTimeInForeground());
+            return Long.compare(b.getTotalTimeInForeground(), a.getTotalTimeInForeground());
         }
     }
 

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

@@ -133,7 +133,7 @@ public class NotificationStation extends SettingsPreferenceFragment {
                 @Override
                 public int compare(HistoricalNotificationInfo lhs,
                                    HistoricalNotificationInfo rhs) {
-                    return (int)(rhs.timestamp - lhs.timestamp);
+                    return Long.compare(rhs.timestamp, lhs.timestamp);
                 }
             };