Deprecation notice added to Desktop Notifications

I've added a warning to the top of Desktop Notifications which explains the changes
and promotes the new Chrome notifications API.

Justin, I reworded this a bit with help from Eric Bidelman (thanks, Eric).

Not too sure if this is what you are looking for.

Also copied Jake here as per Eric's request as he will be drafting new HTML5 rocks content.

BUG=182000
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=193422

[dewittj, 2013-04-10 16:35:06]

Could you mention the particular function
webkitNotifications.createHTMLNotification as deprecated?

[mkearney1, 2013-04-10 18:10:19]

On 2013/04/10 16:35:06, dewittj wrote:
> Could you mention the particular function
> webkitNotifications.createHTMLNotification as deprecated?

Done.

[mkearney1, 2013-04-10 18:10:44]

Warning has been updated to include deprecated method.

[dewittj, 2013-04-10 18:15:05]

lgtm with one comment

https://codereview.chromium.org/13976002/diff/3001/chrome/common/extensions/d...
File chrome/common/extensions/docs/templates/articles/desktop_notifications.html
(right):

https://codereview.chromium.org/13976002/diff/3001/chrome/common/extensions/d...
chrome/common/extensions/docs/templates/articles/desktop_notifications.html:4:
The <code>webKitNotifications.createHTMLNotification()</code> in the
probably need the word "function" in here somewhere, or remove the "The".

[mkearney1, 2013-04-10 18:21:52]

Committed patchset #3 manually as r193422 (presubmit successful).