Add TaskPriority as a parameter to SequencedWorkerPool in preparation for TaskScheduler experiment.

chrome/service/service_process.cc

Index: chrome/service/service_process.cc
diff --git a/chrome/service/service_process.cc b/chrome/service/service_process.cc
index bea34bb8783206f4345369216e18ec5315343244..0b6af0ebe84496c13c14436f6757c5cce910d696 100644
--- a/chrome/service/service_process.cc
+++ b/chrome/service/service_process.cc
@@ -154,7 +154,8 @@ bool ServiceProcess::Initialize(base::MessageLoopForUI* message_loop,
     Teardown();
     return false;
   }
-  blocking_pool_ = new base::SequencedWorkerPool(3, "ServiceBlocking");
+  blocking_pool_ = new base::SequencedWorkerPool(
+      3, "ServiceBlocking", base::TaskPriority::USER_VISIBLE);
 
   // Initialize Mojo early so things can use it.
   mojo::edk::Init();