Fix the build.

Change-Id: I9b9e26e22a6be27341f4b0b95cb8edd1629fa812

Author: sganov

core/java/android/widget/ActivityChooserModel.java

@@ -21,6 +21,7 @@
 import android.content.Intent;
 import android.content.pm.ResolveInfo;
 import android.database.DataSetObservable;
+import android.database.DataSetObserver;
 import android.os.AsyncTask;
 import android.text.TextUtils;
 import android.util.Log;