Use TaskScheduler instead of WorkerPool in fake_cros_disks_client.cc.

chromeos/disks/disk_mount_manager_unittest.cc

Index: chromeos/disks/disk_mount_manager_unittest.cc
diff --git a/chromeos/disks/disk_mount_manager_unittest.cc b/chromeos/disks/disk_mount_manager_unittest.cc
index 6d1cc5d549f74b65567ac56cf4cc698504d4c68b..2f653ebef8e4435dd7c013b7fd7471c38bdcc683 100644
--- a/chromeos/disks/disk_mount_manager_unittest.cc
+++ b/chromeos/disks/disk_mount_manager_unittest.cc
@@ -10,6 +10,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
+#include "base/test/scoped_task_scheduler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/fake_cros_disks_client.h"
 #include "chromeos/disks/disk_mount_manager.h"
@@ -405,7 +406,7 @@ std::ostream& operator<<(std::ostream& stream,
 
 class DiskMountManagerTest : public testing::Test {
  public:
-  DiskMountManagerTest() {}
+  DiskMountManagerTest() : scoped_task_scheduler_(&message_loop_) {}
   ~DiskMountManagerTest() override {}
 
   // Sets up test dbus tread manager and disks mount manager.
@@ -480,7 +481,10 @@ class DiskMountManagerTest : public testing::Test {
  protected:
   chromeos::FakeCrosDisksClient* fake_cros_disks_client_;
   std::unique_ptr<MockDiskMountManagerObserver> observer_;
+
+ private:
   base::MessageLoopForUI message_loop_;
+  base::test::ScopedTaskScheduler scoped_task_scheduler_;
 };
 
 // Tests that the observer gets notified on attempt to format non existent mount