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

content/browser/browser_thread_impl.cc

Index: content/browser/browser_thread_impl.cc
diff --git a/content/browser/browser_thread_impl.cc b/content/browser/browser_thread_impl.cc
index 669a29387f4bfbcdd506b08f00d961f4eb92bbfa..55be5b34f47cae32d187bf1b239dd3384bb5611d 100644
--- a/content/browser/browser_thread_impl.cc
+++ b/content/browser/browser_thread_impl.cc
@@ -100,7 +100,10 @@ base::LazyInstance<BrowserThreadTaskRunners>::Leaky g_task_runners =
 
 struct BrowserThreadGlobals {
   BrowserThreadGlobals()
-      : blocking_pool(new base::SequencedWorkerPool(3, "BrowserBlocking")) {
+      : blocking_pool(
+            new base::SequencedWorkerPool(3,
+                                          "BrowserBlocking",
+                                          base::TaskPriority::USER_VISIBLE)) {
     memset(threads, 0, BrowserThread::ID_COUNT * sizeof(threads[0]));
     memset(thread_delegates, 0,
            BrowserThread::ID_COUNT * sizeof(thread_delegates[0]));