Add method to get find element's response key name

[vkatsikaros]

Workaround for #291

Command find element returns data, in the form {"key"=>"value"} where
key is a generic string "ELEMENT" and value the element id.

geckodriver (firefox's webdriver proxy) no longer use the key name
"ELEMENT", but instead the key name "element-6066-11e4-a52e-4f735466cecf"
So, the method was added to overide the value.

[gempesaw]

Huh, I had also run into this for another issue but I didn't realize it was a magic string - just figured it was a random UUID. But, lo and behold, the spec specifies that exact string!

That being said, thanks for the PR and reminding me that forgot to push up my commits. I definitely appreciate the effort, but I think it makes more sense for the resolution to exist in WebElement instead of only applicable to geckodriver and Selenium::Firefox. That way, if/when other browser drivers conform with the spec (and the actual selenium server standalone jar as well), we won't have to change anything else.

Cheers!

[gempesaw]

blergh, on the other hand, your implementation makes some things way easier, like for example switch_to_frame's endpoint actually cares very much about us sending ELEMENT to SRD and element-6066... to geckodriver. Without the appropriate key for the appropriate driver, it blows up. Luckily, we can send both, which is kinda sloppy, but....

So it's not quite enough for WebElement to be able to consume either one, it needs to also output either/both. man, this is a bit of a headache :c

[vkatsikaros]

Let me know if I can be of assistance for either implementation!