Set GuestOsExternalProtocol feature enabled by default

Bug: b/168506505
Change-Id: Icb2ec0c51e8257416aa5eaf102fca8aa18051203
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2462983Reviewed-by: Jason Lin <lxj@google.com>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816025}

chromeos/constants/chromeos_features.cc

@@ -339,7 +339,7 @@ const base::Feature kGesturePropertiesDBusService{
 
 // Enable Guest OS external protocol handling.
 const base::Feature kGuestOsExternalProtocol{"GuestOsExternalProtocol",
-                                             base::FEATURE_DISABLED_BY_DEFAULT};
+                                             base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Enables editing with handwriting gestures within the virtual keyboard.
 const base::Feature kHandwritingGestureEditing{