before it remove the list, it must derefence the items to free them properly.
ex)
EINA_LIST_FREE(pd->vp_list, vp)

efl_unref(vp);

++reference.
efl_ref(value_provider);

I think ex vp can be just removed from the list and replaced with value_provider. thats' it. don't need to copy properties.

Seems this method doesn't necessary.

This shouldn't be exposed.

Can we say this Value_Provider is a type of Color or Shape?
Please check shape and path whether this value_provider is satisfied with their spec.

I'd rather consider clear interfaces for overridable value list....

class value_provider {
@property keypath:
@property transform:
@property stroke_color:
..

Done.

};

I think we need a secure code if user missed adding the keypath.
if (!keypath) ERR("...") return;

do we need to free eina_stringshare_del(pd->keypath); ??

how about just "transform_set" ?

Let's remove this exceptional handling, user can easily figure out as the result color would look wrong.

//Exception Handling.
if (r < 0) r = 0;
if (g < 0) g = 0;
if (b < 0) b = 0;
if (a > 255) a = 255;
else if (a < 0) a = 0;

if (r > a)
  {
     r = a;
     perr = EINA_TRUE;
  }
if (g > a)
  {
     g = a;
     perr = EINA_TRUE;
  }
if (b > a)
  {
     b = a;
     perr = EINA_TRUE;
  }

if (perr) ERR("Evas only handles pre-multiplied color!");

Remove here exception as well.

Eina_Stringshare *