Merge "Allow apps to downgrade importance in createNotificationChannel" into oc-mr1-dev

     * Creates a notification channel that notifications can be posted to.

     *

     * This can also be used to restore a deleted channel and to update an existing channel's

     * name and description.

     * name, description, and/or importance.

     *

     * <p>The name and description should only be changed if the locale changes

     * or in response to the user renaming this channel. For example, if a user has a channel

     * named 'John Doe' that represents messages from a 'John Doe', and 'John Doe' changes his name

     * to 'John Smith,' the channel can be renamed to match.

     *

     * <p>The importance of an existing channel will only be changed if the new importance is lower

     * than the current value and the user has not altered any settings on this channel.

     *

     * All other fields are ignored for channels that already exist.

     *

     * @param channel  the channel to create.  Note that the created channel may differ from this

            existing.setDescription(channel.getDescription());

            existing.setBlockableSystem(channel.isBlockableSystem());

            // Apps are allowed to downgrade channel importance if the user has not changed any

            // fields on this channel yet.

            if (existing.getUserLockedFields() == 0 &&

                    channel.getImportance() < existing.getImportance()) {

                existing.setImportance(channel.getImportance());

            }

            updateConfig();

            return;

        }