Support callback param for CKEDITOR.editor::setData

[garry.yao]

In order to comply with the asynchronous nature of 'setData' in wysiwyg mode, the user need to listen for a internal "contentDom" event for the very early access to a fully loaded document, we should provide a simpler form API like editor.setData( data, callback ).

Correspondingly, the 'afterSetData' event which already existed now should be fired right before we invoke this callback function, so user could make their choice between these two approaches.

[garry.yao]

Tidied up the description a bit.

[garry.yao]

Ticket Test added at : ​http://ckeditor.t/tt/4445/1(2).html

[fredck]

There are several issues to be considered here:

1. ​Coding style: this thing is happening frequently, so it's better to point it out. The curly braces are optional for if/else/while/for blocks only if the block code is composed by a single line of code. Therefore line 590 in _source/core/editor.js is wrong.

2. The "contentDom" solution pointed out in the ticket description is actually available for the WYSIWYG mode only. We must still consider that setData can be called in any mode, including Source mode. At this point, it makes sense introducing a new event, called "dataReady" that is thrown by each of the mode plugins. This event could be used by the setData function to call the callback.

3. The editor._.isLoadingData trick is not needed anymore at this point, as we must guarantee that the "dataReady" event will be always fired, so we can safely use it only.

4. I don't get the point about having to 300ms delay. This is not a "short delay" in any way, and quite undesirable.

[garry.yao]

Coming with a new patch targeting Fred's proposal.

[fredck]

I'm not being able to apply the patch on _source/plugins/sourcearea/plugin.js and _source/core/editor.js, probably due to the "?" at the start of the files. Can you please update your local copy and create the patch again, without those changes at line 1 in those files.

Also, instead of purely call callback(), lets do instead callback.call( editor ), just to make it more flexible.

[garry.yao]

Ticket Test was updated at : ​http://ckeditor.t/tt/4445/1(2).html

[fredck]

The above TC, other than pointing to the wrong URL, doesn't fail currently. The page actually gets broken. works well after the patch though.

[garry.yao]

Fixed with [4354] (including the TC fixes).