diff --git a/common/subprocess_unittest.cc b/common/subprocess_unittest.cc
index 8dbaa0b..19b24f4 100644
--- a/common/subprocess_unittest.cc
+++ b/common/subprocess_unittest.cc
@@ -45,6 +45,7 @@
 using base::TimeDelta;
 using brillo::MessageLoop;
 using std::string;
+using std::unique_ptr;
 using std::vector;
 
 namespace {
@@ -73,6 +74,7 @@
   brillo::BaseMessageLoop loop_{&base_loop_};
   brillo::AsynchronousSignalHandler async_signal_handler_;
   Subprocess subprocess_;
+  unique_ptr<base::FileDescriptorWatcher::Controller> watcher_;
 };
 
 namespace {
@@ -256,21 +258,23 @@
   int fifo_fd = HANDLE_EINTR(open(fifo_path.c_str(), O_RDONLY));
   EXPECT_GE(fifo_fd, 0);
 
-  loop_.WatchFileDescriptor(FROM_HERE,
-                            fifo_fd,
-                            MessageLoop::WatchMode::kWatchRead,
-                            false,
-                            base::Bind(
-                                [](int fifo_fd, uint32_t tag) {
-                                  char c;
-                                  EXPECT_EQ(1,
-                                            HANDLE_EINTR(read(fifo_fd, &c, 1)));
-                                  EXPECT_EQ('X', c);
-                                  LOG(INFO) << "Killing tag " << tag;
-                                  Subprocess::Get().KillExec(tag);
-                                },
-                                fifo_fd,
-                                tag));
+  watcher_ = base::FileDescriptorWatcher::WatchReadable(
+      fifo_fd,
+      base::Bind(
+          [](unique_ptr<base::FileDescriptorWatcher::Controller>* watcher,
+             int fifo_fd,
+             uint32_t tag) {
+            char c;
+            EXPECT_EQ(1, HANDLE_EINTR(read(fifo_fd, &c, 1)));
+            EXPECT_EQ('X', c);
+            LOG(INFO) << "Killing tag " << tag;
+            Subprocess::Get().KillExec(tag);
+            *watcher = nullptr;
+          },
+          // watcher_ is no longer used outside the clousure.
+          base::Unretained(&watcher_),
+          fifo_fd,
+          tag));
 
   // This test would leak a callback that runs when the child process exits
   // unless we wait for it to run.