[giunatale]

The focus highlight (the outline showing which element is selected when navigating with a D-pad or a car's rotary controller) never worked on YouTube. Two commits:

• Fix the focus highlight on pages that require Trusted Types. addFocusHighlight() set the style through innerHTML, which YouTube blocks: every page load logged Failed to set the 'innerHTML' property on 'Element': This document requires 'TrustedHTML' assignment, and nothing was highlighted. It now sets the style's textContent, which Trusted Types doesn't restrict.
• Show the focus highlight only for key navigation. Once working, the highlight outlined whatever was last tapped, and a page that focuses an element when it loads (YouTube focuses its logo) got it before anything was pressed. The style is now added only after the first navigation key (D-pad, rotary controller, arrow keys), and uses :focus-visible, so taps after that aren't outlined either.

Tested on a OnePlus 12 (Android 16) by inspecting Fermata's WebView: no console error, no outline when the page loads or after taps, and the outline appearing and moving through the page with adb shell input keyevent KEYCODE_DPAD_DOWN.

[AndreyPavlenko]

Review of the textContent fix and the key-navigation gate.

Correct

• innerHTML to textContent fixes the Trusted Types error.
• :focus-visible plus the key gate is reasonable. Keep the gate, since a script that focuses an element on load can still match :focus-visible.

Issues

1. Filter accepts almost any key. !event.isSystem() lets letters, digits, Enter and Space through, so typing in a search box turns the highlight on. The comment and description say "navigation key", but the code does not check for one. Restrict to navigation keys, e.g. KEYCODE_DPAD_UP/DOWN/LEFT/RIGHT, KEYCODE_DPAD_CENTER, KEYCODE_TAB.
2. Rotary input may not reach dispatchKeyEvent. Some rotary controllers send MotionEvent ACTION_SCROLL (AXIS_SCROLL) instead of key events. Testing used adb input keyevent only. Verify on real car hardware, or also handle dispatchGenericMotionEvent.
3. Duplicate <style> elements. The style is added on every pageLoaded, and YouTube is an SPA, so pageLoaded can fire repeatedly on one document. Give the element an id and skip if present:

   if (document.getElementById('fermata-focus')) return;
   style.id = 'fermata-focus';

4. Minor: if the first key arrives during page load, document.head may be null. Use (document.head || document.documentElement).
5. Minor: keyNavigation never resets for the view's lifetime. Probably intended, but make it a deliberate choice.

Verdict: request changes for 1 and 3. Item 2 needs hardware testing or an explicit note that it is untested.

Reviewed by Claude

[giunatale]

Review of the textContent fix and the key-navigation gate.

Correct

• innerHTML to textContent fixes the Trusted Types error.
• :focus-visible plus the key gate is reasonable. Keep the gate, since a script that focuses an element on load can still match :focus-visible.

Issues

1. Filter accepts almost any key. !event.isSystem() lets letters, digits, Enter and Space through, so typing in a search box turns the highlight on. The comment and description say "navigation key", but the code does not check for one. Restrict to navigation keys, e.g. KEYCODE_DPAD_UP/DOWN/LEFT/RIGHT, KEYCODE_DPAD_CENTER, KEYCODE_TAB.
2. Rotary input may not reach dispatchKeyEvent. Some rotary controllers send MotionEvent ACTION_SCROLL (AXIS_SCROLL) instead of key events. Testing used adb input keyevent only. Verify on real car hardware, or also handle dispatchGenericMotionEvent.
3. Duplicate <style> elements. The style is added on every pageLoaded, and YouTube is an SPA, so pageLoaded can fire repeatedly on one document. Give the element an id and skip if present:
   if (document.getElementById('fermata-focus')) return;
   style.id = 'fermata-focus';
4. Minor: if the first key arrives during page load, document.head may be null. Use (document.head || document.documentElement).
5. Minor: keyNavigation never resets for the view's lifetime. Probably intended, but make it a deliberate choice.

Verdict: request changes for 1 and 3. Item 2 needs hardware testing or an explicit note that it is untested.

Reviewed by Claude

Thanks! Addressed basically everything:

1. Filter: only navigation input turns the highlight on now: KEYCODE_DPAD_UP/DOWN/LEFT/RIGHT, KEYCODE_DPAD_CENTER, KEYCODE_TAB and KEYCODE_NAVIGATE_NEXT/PREVIOUS. Typing no longer does.
2. Rotary: dispatchGenericMotionEvent also turns it on for ACTION_SCROLL from SOURCE_ROTARY_ENCODER. Untested on hardware: my car only has a touch screen, so this part is tested with adb input keyevent only.
3. Duplicate <style>: the element has the id fermata-focus and isn't added again if it's there.
4. document.head: falls back to document.documentElement.
5. keyNavigation never resets: intended. Whoever navigated with keys keeps using the same controller, so it stays on for the view's lifetime; the comment now says so.

Also rebased on master.