Set radius for secondary web view and focus border

[sangwoo108]

Resolves brave/brave-browser#37924

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  • npm run test -- brave_browser_tests, npm run test -- brave_unit_tests wiki
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  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
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  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

[simonhong]

It seems web view's radius is not set properly in split view like below.

[sangwoo108]

Hum, that seems to be left side of the focused web view(main contents webview). I'll take a look.

[sangwoo108]

@simonhong , that was related to this TODO() part. Disabled devtools placement code temporarily.

[simonhong]

++ 👍🏼