Migrate remaining NOTREACHED()s in chrome/

NOTREACHED() and NOTREACHED_IN_MIGRATION() are both CHECK-fatal now.
The former is [[noreturn]] so this CL also performs dead-code removal
after the NOTREACHED().

This CL does not attempt to do additional rewrites of any surrounding
code, like:

if (!foo) {
  NOTREACHED();
}

to CHECK(foo);

Those transforms take a non-trivial amount of time (and there are
thousands of instances). Cleanup can be left as an exercise for the
reader.

Bug: 40580068
Change-Id: Ia63ab8e98bee27838be25102c5ee573d919aba5b
Cq-Include-Trybots: luci.chromium.try:linux-dcheck-off-rel
Low-Coverage-Reason: OTHER Should-be-unreachable code
Validate-Test-Flakiness: skip
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5998172
Reviewed-by: Erik Chen <[email protected]>
Auto-Submit: Peter Boström <[email protected]>
Commit-Queue: Sam McNally <[email protected]>
Commit-Queue: Peter Boström <[email protected]>
Reviewed-by: Sam McNally <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1379339}
diff --git a/chrome/browser/webid/federated_identity_api_permission_context.cc b/chrome/browser/webid/federated_identity_api_permission_context.cc
index c25956df..edb39c9 100644
--- a/chrome/browser/webid/federated_identity_api_permission_context.cc
+++ b/chrome/browser/webid/federated_identity_api_permission_context.cc
@@ -49,8 +49,7 @@
     case CONTENT_SETTING_BLOCK:
       return PermissionStatus::BLOCKED_SETTINGS;
     default:
-      NOTREACHED_IN_MIGRATION();
-      return PermissionStatus::BLOCKED_SETTINGS;
+      NOTREACHED();
   }
 
   if (permission_autoblocker_->IsEmbargoed(