Use TaskScheduler instead of WorkerPool in platform_keys.cc.

chrome/browser/chromeos/platform_keys/platform_keys.cc

Index: chrome/browser/chromeos/platform_keys/platform_keys.cc
diff --git a/chrome/browser/chromeos/platform_keys/platform_keys.cc b/chrome/browser/chromeos/platform_keys/platform_keys.cc
index ea709640db55cf532f855ff5690eca94806c6c7c..cc3ca6f56f2201530aa3d3bec269a9ed5c86c473 100644
--- a/chrome/browser/chromeos/platform_keys/platform_keys.cc
+++ b/chrome/browser/chromeos/platform_keys/platform_keys.cc
@@ -10,7 +10,7 @@
 #include "base/bind_helpers.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
-#include "base/threading/worker_pool.h"
+#include "base/task_scheduler/post_task.h"
 #include "net/base/hash_value.h"
 #include "net/cert/x509_certificate.h"
 
@@ -66,13 +66,17 @@ void IntersectCertificates(
         callback) {
   std::unique_ptr<net::CertificateList> intersection(new net::CertificateList);
   net::CertificateList* const intersection_ptr = intersection.get();
-  if (!base::WorkerPool::PostTaskAndReply(
-          FROM_HERE, base::Bind(&IntersectOnWorkerThread, certs1, certs2,
-                                intersection_ptr),
-          base::Bind(callback, base::Passed(&intersection)),
-          false /* task_is_slow */)) {
-    callback.Run(base::WrapUnique(new net::CertificateList));
-  }
+
+  // This is triggered by a call to the
+  // chrome.platformKeys.selectClientCertificates extensions API. Completion
+  // does not affect browser responsiveness, hence the BACKGROUND priority.
+  base::PostTaskWithTraitsAndReply(
+      FROM_HERE, base::TaskTraits()
+                     .WithPriority(base::TaskPriority::BACKGROUND)
+                     .WithShutdownBehavior(
+                         base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN),
+      base::Bind(&IntersectOnWorkerThread, certs1, certs2, intersection_ptr),
+      base::Bind(callback, base::Passed(&intersection)));
 }
 
 }  // namespace platform_keys