[CCA] Enlarge switch device focus ring to 56px

Bug: 877599
Change-Id: I958b78bef4aeffe2906463afd7ca78b7164a3c4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1978541
Commit-Queue: Kuo Jen Wei <inker@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Auto-Submit: Kuo Jen Wei <inker@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#726730}

chrome/browser/resources/chromeos/camera/src/css/main.css

@@ -400,6 +400,13 @@ body.mode-switching:not(.streaming) #camera-mode {
   }
 }
 
+body.tab-navigation #switch-device:focus::after {
+  bottom: -8px;
+  left: -8px;
+  right: -8px;
+  top: -8px;
+}
+
 #gallery-enter {
   background-color: rgba(24, 24, 24, 1);
   background-size: cover;