Context sensitive insertHtml

[Garry Yao]

We've seen various paste problems caused by our current implementation of CKEDITOR.editor::insertHtml, now rely on browsers' native API, which is buggy and inconsistent.
While we do have other options here: The idea is to implement an DTD aware, context sensitive insertion based on CKEDITOR.htmlParser' and 'CKEDITOR.editor::insertElement', this should be able to extinguish all weird bugs around.

Related tickets are:

#5696

IE : Cursor moves to the start of paragraph in the Pasted Text

#5367

Implement editor.insertText and use it in the special chars dialog

#5536

Problems with pasting (executing insertHtml) and formatted text

#5170

Problems with pasting (executing insertHtml) and formatted text

#5033

Invalid behavior when inserting nested divs with insertHtml()

#4898

Paste: After pasting a table from word it is not possible to navigate outside the table

#4746

insertHtml left trim text

#3105

insertHtml and insertElement should agree on the result

#2781

FckEditor InsertHtml inserts extra <p> tags

#2749

InsertHtml() is inconsistent between IE 7 and Firefox 2

#2526

InsertHTML Problem

#503

Unordered list paste: doesn't work correctly in IE

[Garry Yao]

Minor adjustments.

[Garry Yao]

By checking the ​insertHtml API in latest HTML5 draft, it also doesn't require a context sensitive insertion:

4. Invoke the HTML fragment parsing algorithm with an arbitrary orphan 'body' element owned by the same Document as the context element and with the value argument as input.

[Garry Yao]

We're over burdened now so this feature will be deferred to next milestone.

[Garry Yao]

Ported a simplified version of Firefox's ​nsHTMLEditor::InsertHTMLWithContext while it supposed to be browser neutral paste implementation.

[Garry Yao]

Align the outdated patch.

[Wiktor Walc]

Might be a duplicate of one of the tickets, but I'm adding it just to have one more test case: #5873

[Sa'ar Zac Elias]

Align the outdated patch

[Garry Yao]

Align outdated patch

[Garry Yao]

New patch with some updates:

1. Instead of using "range::extractContent" which is currently buggy when dealing with list and table selection, we now play a browser trick (insertHtml called with an empty content) to achieve the same result;
2. Introduce a HTML parser param (clipboard) to handle the case when parsing context of the fragment is unknown, where we should not touch the white-spaces children of the fragment.

[Garry Yao]

It looks like a huge task to make a reviewing here, so let me also propose some orders here:

1. First we check there's no exception thrown in any case when pasting, this must be guaranteed;
2. Then we should check paste in any case should not result in malformed structure (DTD valid);
3. Finally it come to a case by case test with different combination of clipboard content and selection type to check the rationality of the result, in case it's amphibolous, we should allow it to be handled out of this ticket.

[Garry Yao]

Trunk alignment.

[Sa'ar Zac Elias]

Please align the patch with the latest updates (data-cke attributes).

[Frederico Caldeira Knabben]

This one, other than introducing a good amount of code into core (justifiable), touches import part of it. We need a lot of attention on it and we'll not be able to safely land this on the SVN for the 3.5.

[Piotrek Koszuliński]

Fixed in 4.0.