ViewPager API update

Change-Id: I3033caefc206c969f172b2dd0e76809a21c15652

samples/Support13Demos/src/com/example/android/supportv13/app/ActionBarTabsPager.java

@@ -134,6 +134,10 @@ public class ActionBarTabsPager extends Activity {
             mActionBar.setSelectedNavigationItem(position);
         }
 
+        @Override
+        public void onPageScrollStateChanged(int state) {
+        }
+
         @Override
         public void onTabSelected(Tab tab, FragmentTransaction ft) {
             Object tag = tab.getTag();