Fix use-after-move in //extensions/browser/api/declarative_net_request/

Fix use-after-move (potential) bugs found by the
"bugprone-use-after-move" clang-tidy check.

Bug: 1122844
Change-Id: I3c2d8c6c5a356af367d84304a7ca7c3d72b9621e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560307
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Auto-Submit: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831140}

extensions/browser/api/declarative_net_request/rules_monitor_service.cc

@@ -745,13 +745,15 @@ void RulesMonitorService::OnDynamicRulesUpdated(
     base::Optional<std::string> error) {
   DCHECK_EQ(1u, load_data.rulesets.size());
 
+  const bool has_error = error.has_value();
+
   LogMetricsAndUpdateChecksumsIfNeeded(load_data);
 
   // Respond to the extension.
   std::move(callback).Run(std::move(error));
 
   RulesetInfo& dynamic_ruleset = load_data.rulesets[0];
-  DCHECK_EQ(dynamic_ruleset.did_load_successfully(), !error.has_value());
+  DCHECK_EQ(dynamic_ruleset.did_load_successfully(), !has_error);
 
   if (!dynamic_ruleset.did_load_successfully())
     return;