Implement SeekBarPreference.onGetDefaultValue

 Bug: 5036325

Change-Id: I1db0ed3809b862a547e5fda40027852f8b46aa38
diff --git a/core/java/android/preference/SeekBarPreference.java b/core/java/android/preference/SeekBarPreference.java
index b8919c2..7133d3a 100644
--- a/core/java/android/preference/SeekBarPreference.java
+++ b/core/java/android/preference/SeekBarPreference.java
@@ -77,6 +77,11 @@
     }
 
     @Override
+    protected Object onGetDefaultValue(TypedArray a, int index) {
+        return a.getInt(index, 0);
+    }
+
+    @Override
     public boolean onKey(View v, int keyCode, KeyEvent event) {
         if (event.getAction() != KeyEvent.ACTION_UP) {
             if (keyCode == KeyEvent.KEYCODE_PLUS