Google search in sticky nav

[benlk]

Changes

• Adds Google Custom Search to the sticky nav search if it's enabled, and styles
• CSS fix for "When you're on the search results page, the top bar breaks and gets a lot bigger." in less/inc/search.less

Search results display in the same popup that they do if you use the search in the global nav. Here's how it looks on mobile:

And the sticky nav item keeps the "Powered by Google" bit:

Why

Requested for YT-35, Largo ticket #730.

Debt

This assumes that the form-containing div created by Google's scripts has the id ___gcse_1. If that changes, the styles will break and the nav will look hideous. We should notice fairly quickly if Google changes that..

[rnagle]

Is there an option to use a separate results page instead? Showing results in the dropdown seems a little weird to me and might not be right for everyone.

The actual search form looks strange to me. The spacing between the text field and submit button could be less. The spacing around the "powered by Google" could be more. Also note the blue button is skewed.

[benlk]

Pushed some changes. I'm not entirely sure what Google is trying to do with the blue button, but it now displays in Chrome, Firefox and Safari like so:

The "Powered by Google" disappeared, because of a Google CSS rule. ¯_(ツ)_/¯

The modal search results dialog is injected by Google's search form in response to the search. The TOS for the custom search require that we not modify the search results or their display in any way, so I don't think we should try to get them to display natively within WordPress. See section 1.4.

[benlk]

Closing in favor of #756