Highlight row (instead of ripple) when come from search.

- Moved HighlightableAdapter to its own class
- Replaced ripple with blue background
- Bluebackground only stays for 5 seconds. After that it's replaced by
  ?attr/selectableBackground

Misc fixes.

- Fix NPE in UserSettings
- Update char limit on a new string

Change-Id: I4687e54e71fd7b9243f520b7630563df58be23d4
Fixes: 71715698
Fixes: 72761974
Test: robotests

src/com/android/settings/users/UserSettings.java

@@ -309,7 +309,7 @@ public class UserSettings extends SettingsPreferenceFragment
     public void onDestroy() {
         super.onDestroy();
 
-        if (!mUserCaps.mEnabled) {
+        if (mUserCaps == null || !mUserCaps.mEnabled) {
             return;
         }