WebUI Omnibox Popup experiment

Debug instructions

• Launch Chrome with --enable-features=WebUIOmniboxPopupDebug or enable it via chrome://flags/#webui-omnibox-popup-debug.
  • For side-by-side comparison with the Views popup, launch Chrome with --enable-features=WebUIOmniboxPopupDebug:SxS/true or select the Side by Side flag variant.
• Navigate to chrome://omnibox-popup.top-chrome?debug in a tab. A blank page should be shown.
• Start typing a query into the omnibox. The omnibox suggestions should be shown within the tab.
• Blur the omnibox for the real popup to close and see only the results in the tab.
• Open DevTools (right click -> Inspect) to debug as usual.

Note: See additional instructions on how to iterate faster using the --load-webui-from-disk flow