Omnibox: Force text field to LTR context if it is a URL.
This means that URLs will be displayed in a left-to-right paragraph
context. Right-to-left runs are still rendered RTL, but will not flip
the whole URL around. For example (if "ABC" is Hebrew), this will render
"ABC.com" as "CBA.com", rather than "com.CBA".
This is consistent with the behaviour in the Omnibox drop-down items
(OmniboxResultView::CreateClassifiedRenderText) and status bubble