A simple QuerySelectorAll command

[captainbrosset]

In response to https://bugzilla.mozilla.org/show_bug.cgi?id=770156 and based on https://gist.github.com/3000231 here is a simple queryselectorall command that could be interesting to you.

It doesn't do much for now apart from listing the matched elements and giving the number of elements matched.

Here is a screenshot:

In the gcli version embedded in the Fx devtools, I know there's an inspect command too, but I think it could benefit from listing all matches rather than forcing the user to write a selector that matches only one element.

Anyway, here's the pull request, up to you.

[captainbrosset]

I totally did not localized strings nor created tests :-)
Doing this now...

[captainbrosset]

Thanks for the review and feedback.

I've rewritten the command to extract the view creation to a converter.
Also, I've added an onclick handler on each matching node. Using util.findCssSelector(element), clicking on a matching node will run qsa again with the unique selector.

To make things a bit cleaner, I've squashed my commits into 1 and signed it off. I'll therefore close this PR in a minute and open a new one with the squashed commits.

About the usefulness of this command, I admit I started working on it mostly as a way to get into gcli. It's true that given the tools we already have in the dev-tools, it doesn't seem very useful at first. However, with the findCssSelector bit, it may start to be a little bit more interesting to developers, giving them hints on how to write their selectors.
Perhaps a way to continue would be to add things around selector performance and specificity, although I can't thing of anything in particular right now.

Thanks for the feedback again.
Patrick

[captainbrosset]

I've just opened PR https://github.com/mozilla/gcli/pull/65 with the latest changes.