Hotlist Slow: Remove extra thread pool created by VolumeMountWatcherWin.

components/storage_monitor/test_volume_mount_watcher_win.cc

Index: components/storage_monitor/test_volume_mount_watcher_win.cc
diff --git a/components/storage_monitor/test_volume_mount_watcher_win.cc b/components/storage_monitor/test_volume_mount_watcher_win.cc
index 77ea57b282f8557a411400a89fcd90d1ec74314b..234b87f78fd9f4e7febd6b715c0dd2e9126f068b 100644
--- a/components/storage_monitor/test_volume_mount_watcher_win.cc
+++ b/components/storage_monitor/test_volume_mount_watcher_win.cc
@@ -11,6 +11,7 @@
 #include "base/files/scoped_temp_dir.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/storage_monitor/storage_info.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace storage_monitor {
 
@@ -108,7 +109,7 @@ void TestVolumeMountWatcherWin::SetAttachedDevicesFake() {
 }
 
 void TestVolumeMountWatcherWin::FlushWorkerPoolForTesting() {
-  device_info_worker_pool_->FlushForTesting();
+  content::BrowserThread::GetBlockingPool()->FlushForTesting();
 }
 
 void TestVolumeMountWatcherWin::DeviceCheckComplete(
@@ -150,8 +151,4 @@ VolumeMountWatcherWin::GetAttachedDevicesCallbackType
   return base::Bind(&FakeGetSingleAttachedDevice);
 }
 
-void TestVolumeMountWatcherWin::ShutdownWorkerPool() {
-  device_info_worker_pool_->Shutdown();
-}
-
 }  // namespace storage_monitor