Deprecate NonThreadSafe in components/captive_portal in favor of SequenceChecker.

components/captive_portal/captive_portal_detector.cc

Index: components/captive_portal/captive_portal_detector.cc
diff --git a/components/captive_portal/captive_portal_detector.cc b/components/captive_portal/captive_portal_detector.cc
index 6ec4df23d667ab2c24811ca9f7d84efd42a6c9ac..a51b809164ae1be9bda0d635851d7d4dc94124bf 100644
--- a/components/captive_portal/captive_portal_detector.cc
+++ b/components/captive_portal/captive_portal_detector.cc
@@ -23,13 +23,14 @@ CaptivePortalDetector::CaptivePortalDetector(
 }
 
 CaptivePortalDetector::~CaptivePortalDetector() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 }
 
 void CaptivePortalDetector::DetectCaptivePortal(
     const GURL& url,
     const DetectionCallback& detection_callback,
     const net::NetworkTrafficAnnotationTag& traffic_annotation) {
-  DCHECK(CalledOnValidThread());
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!FetchingURL());
   DCHECK(detection_callback_.is_null());
 
@@ -60,7 +61,7 @@ void CaptivePortalDetector::Cancel() {
 }
 
 void CaptivePortalDetector::OnURLFetchComplete(const net::URLFetcher* source) {
-  DCHECK(CalledOnValidThread());
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(FetchingURL());
   DCHECK_EQ(url_fetcher_.get(), source);
   DCHECK(!detection_callback_.is_null());