Replace deprecated base::NonThreadSafe in chrome in favor of SequenceChecker.

chrome/browser/process_singleton_startup_lock.cc

Index: chrome/browser/process_singleton_startup_lock.cc
diff --git a/chrome/browser/process_singleton_startup_lock.cc b/chrome/browser/process_singleton_startup_lock.cc
index f564de7dca4da21c89b560512f13e31ad90484b5..939fb2365ec6405678d7181378c674ee7b4f9bcb 100644
--- a/chrome/browser/process_singleton_startup_lock.cc
+++ b/chrome/browser/process_singleton_startup_lock.cc
@@ -12,7 +12,9 @@ ProcessSingletonStartupLock::ProcessSingletonStartupLock(
     : locked_(true),
       original_callback_(original_callback) {}
 
-ProcessSingletonStartupLock::~ProcessSingletonStartupLock() {}
+ProcessSingletonStartupLock::~ProcessSingletonStartupLock() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+}
 
 ProcessSingleton::NotificationCallback
 ProcessSingletonStartupLock::AsNotificationCallback() {
@@ -21,7 +23,7 @@ ProcessSingletonStartupLock::AsNotificationCallback() {
 }
 
 void ProcessSingletonStartupLock::Unlock() {
-  DCHECK(CalledOnValidThread());
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   locked_ = false;
 
   // Replay the command lines of the messages which were received while the