Use content::RunBlockingPoolTask() in tests.

chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc

Index: chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc b/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
index 2c9d844c2734843c481859b2f244910ce524850c..646c51351737f7bc6061321da469ad5854cabe4f 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
@@ -521,7 +521,7 @@ IN_PROC_BROWSER_TEST_F(KioskAppManagerTest, RemoveApp) {
 
   // Remove the app now.
   manager()->RemoveApp(kTestLocalFsKioskApp);
-  content::BrowserThread::GetBlockingPool()->FlushForTesting();
+  content::RunAllBlockingPoolTasksUntilIdle();
   manager()->GetApps(&apps);
   ASSERT_EQ(0u, apps.size());
   EXPECT_FALSE(base::PathExists(crx_path));
@@ -603,7 +603,7 @@ IN_PROC_BROWSER_TEST_F(KioskAppManagerTest, UpdateAndRemoveApp) {
 
   // Remove the app now.
   manager()->RemoveApp(kTestLocalFsKioskApp);
-  content::BrowserThread::GetBlockingPool()->FlushForTesting();
+  content::RunAllBlockingPoolTasksUntilIdle();
   manager()->GetApps(&apps);
   ASSERT_EQ(0u, apps.size());
   // Verify both v1 and v2 crx files are removed.