Migrate module support

Patch applied cleanly and works fine.

I also went ahead and created a module for anyone needing this functionality but not wanting to apply the patch.

https://drupal.org/sandbox/daveparrish/2110595

Patch committed! 8f6de9e

Thank you very much rvilar!

I can second @tannerjfco's experience in #2318077: Issues with Migrate Field Handler, in that mapping to the :video_url subfield imports nothing, but if I import to my video field without the subfield:

$this->addFieldMapping('field_video', 'my_video_url');

as compared to

$this->addFieldMapping('field_video:video_url', 'my_video_url');

where the my_video_url source field is a custom value generated in prepareRow(), is it works just fine.

In running through the prepare() function for the handler, my mapped value comes in in $values['arguments'], and once that gets unset, there's nothing left in $values, so FALSE is returned. Any chance someone could give an example of how this is supposed to be used, if not just as a straight mapping like I showed above?

Thanks.

In general, the primary field value should be set without a subfield. This is the case for most fields, so videos ought to be the same. For example, for an ordinary text field you would also use

$this->addFieldMapping('field_text', 'my_text');

not

$this->addFieldMapping('field_text:value', 'my_text');

Subfields for video embed fields could be improved - see #2472687: Video embed field Migration subfields.