XWIKI-16389: Dedicated macro for inline editing of wikimacro content

[surli]

Issue

https://jira.xwiki.org/browse/XWIKI-16389

Solution

• Create a dedicated macro for wikimacro content that insert the content of a wikimacro and put a dedicated metadata around it for inline editing
• Process in DefaultWikiMacroRenderer the rendered wikimacro to remove the macro markers that could prevent from inline editing.

Test

Unit tests has been added to the new module and some manual tests have been performed.
I mostly use this macro for testing manually my changes:

{{velocity}}
{{box}}
{{wikimacrocontent/}}
{{/box}}

This content is $xcontext.macro.content.length() characters length.
{{/velocity}}

I needed the fix provided for https://jira.xwiki.org/browse/XRENDERING-562 (see xwiki/xwiki-rendering#174) to avoid some issues with the two consecutive metadatablocks created by box macro and wikimacrocontent.
I'm able to inline edit the content of this macro with this change and the fix from xwiki-rendering.

However I encountered an issue when adding inside the macro box an error macro when inline editing it: it seems that any content added after the error box is removed when saving from the inline editor. I suspect another issue from xwiki-rendering.

[mflorea]

I'm not sure this is the main use case:

{{velocity}}
{{box}}
{{wikimacrocontent/}}
{{/box}}

IMO the main use case is: being able to implement a wiki-based rendering macro whose content can be edited in-line in the WYSIWYG editor. The code of the macro will look like this most of the time:

{{velocity}}
{{html clean="false"}}
<div ...><!-- Some wrapping around the content that may depend on the macro parameters  -->
  ...
  <!-- Output the macro content here so that it can be edited in-line in the WYSIWYG editor. -->
  ...
</div>
{{/html}}
{{/velocity}}

IMO someone developing a wiki-based rendering macro will want to:

• use scripting macros (such as Velocity or Groovy) in order to access the macro content and parameters
• use the HTML macro (not wiki syntax) for the wrapping around the macro content (because it's UI)

An example of such a macro could be:

{{figure src="someImage.png"}}some description{{/figure}}

The macro code would look like this:

{{velocity}}
{{html clean="false"}}
<div class="figure">
  <div class="figure-image-wrapper">
    <img src="..." class="figure-image" />
  </div>
  <div class="figure-caption">
    <!-- Output the figure caption here so that it can be edited in-line in the WYSIWYG editor. -->
  </div>
</div>
{{/html}}
{{/velocity}}

To conclude: I don't think wikimacrocontent is that useful (if it's only purpose is to help you output the non-generated-content DIV).

[surli]

@mflorea so after our mail exchange, do you agree with this macro? I don't have much time until the release so I'd like to merge this one.

[mflorea]

@surli OK, go. We can improve it later.