Android: make OneSignalDbContract package-private

- Xamarin was having issues with BaseColumns
so this class was made package-private as a
result.

Author: Vivek Ayer

OneSignalSDK/onesignal/src/main/java/com/onesignal/OneSignalDbContract.java

@@ -29,28 +29,28 @@
 
 import android.provider.BaseColumns;
 
-public class OneSignalDbContract {
-   public OneSignalDbContract() {}
+class OneSignalDbContract {
+   OneSignalDbContract() {}
 
-   public static abstract class NotificationTable implements BaseColumns {
-      public static final String TABLE_NAME = "notification";
-      public static final String COLUMN_NAME_NOTIFICATION_ID = "notification_id"; // OneSignal Notification Id
-      public static final String COLUMN_NAME_ANDROID_NOTIFICATION_ID = "android_notification_id";
-      public static final String COLUMN_NAME_GROUP_ID = "group_id";
-      public static final String COLUMN_NAME_IS_SUMMARY = "is_summary";
-      public static final String COLUMN_NAME_OPENED = "opened";
-      public static final String COLUMN_NAME_DISMISSED = "dismissed";
-      public static final String COLUMN_NAME_TITLE = "title";
-      public static final String COLUMN_NAME_MESSAGE = "message";
-      public static final String COLUMN_NAME_CREATED_TIME = "created_time";
+   static abstract class NotificationTable implements BaseColumns {
+      static final String TABLE_NAME = "notification";
+      static final String COLUMN_NAME_NOTIFICATION_ID = "notification_id"; // OneSignal Notification Id
+      static final String COLUMN_NAME_ANDROID_NOTIFICATION_ID = "android_notification_id";
+      static final String COLUMN_NAME_GROUP_ID = "group_id";
+      static final String COLUMN_NAME_IS_SUMMARY = "is_summary";
+      static final String COLUMN_NAME_OPENED = "opened";
+      static final String COLUMN_NAME_DISMISSED = "dismissed";
+      static final String COLUMN_NAME_TITLE = "title";
+      static final String COLUMN_NAME_MESSAGE = "message";
+      static final String COLUMN_NAME_CREATED_TIME = "created_time";
 
       // JSON formatted string of the full GCM bundle
-      public static final String COLUMN_NAME_FULL_DATA = "full_data";
+      static final String COLUMN_NAME_FULL_DATA = "full_data";
 
 
-      public static final String INDEX_CREATE_NOTIFICATION_ID = "CREATE INDEX notification_notification_id_idx ON notification(notification_id); ";
-      public static final String INDEX_CREATE_ANDROID_NOTIFICATION_ID = "CREATE INDEX notification_android_notification_id_idx ON notification(android_notification_id); ";
-      public static final String INDEX_CREATE_GROUP_ID = "CREATE INDEX notification_group_id_idx ON notification(group_id); ";
-      public static final String INDEX_CREATE_CREATED_TIME = "CREATE INDEX notification_created_time_idx ON notification(created_time); ";
+      static final String INDEX_CREATE_NOTIFICATION_ID = "CREATE INDEX notification_notification_id_idx ON notification(notification_id); ";
+      static final String INDEX_CREATE_ANDROID_NOTIFICATION_ID = "CREATE INDEX notification_android_notification_id_idx ON notification(android_notification_id); ";
+      static final String INDEX_CREATE_GROUP_ID = "CREATE INDEX notification_group_id_idx ON notification(group_id); ";
+      static final String INDEX_CREATE_CREATED_TIME = "CREATE INDEX notification_created_time_idx ON notification(created_time); ";
    }
 }