Enable CSS :focus-visible and Accessibility Focus Highlight preference

Bug: 1094565, 817199
Change-Id: Ibf5cea41aa43d5e6f932df69a0b589d8e1d57015
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2277660Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#786103}

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -423,7 +423,7 @@
     },
     {
       name: "CSSFocusVisible",
-      status: "experimental",
+      status: "stable",
     },
     {
       name: "CSSFoldables",

ui/accessibility/accessibility_features.cc

@@ -48,7 +48,7 @@ bool IsAccessibilityTreeForViewsEnabled() {
 }
 
 const base::Feature kAccessibilityFocusHighlight{
-    "AccessibilityFocusHighlight", base::FEATURE_DISABLED_BY_DEFAULT};
+    "AccessibilityFocusHighlight", base::FEATURE_ENABLED_BY_DEFAULT};
 
 bool IsAccessibilityFocusHighlightEnabled() {
   return base::FeatureList::IsEnabled(::features::kAccessibilityFocusHighlight);