Improve the debugging output for invalid states in BrowsingDataCounter

This is needed to debug a NOTREACHED() hit in crbug.com/1381078.

Bug: 1381078
Change-Id: Ib880fe9c06d76f1f5beaa52a07c25764add3936a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4020666
Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Commit-Queue: Martin Šrámek <msramek@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1070245}

components/browsing_data/core/counters/browsing_data_counter.cc

@@ -114,8 +114,11 @@ void BrowsingDataCounter::ReportResult(std::unique_ptr<Result> result) {
       staged_result_ = std::move(result);
       return;
     case State::IDLE:
+      NOTREACHED() << "State::IDLE";
+      return;
     case State::REPORT_STAGED_RESULT:
-      NOTREACHED();
+      NOTREACHED() << "State::REPORT_STAGED_RESULT";
+      return;
   }
 }