Use FileDescriptorWatcher in FilePathWatcherKQueue.

components/policy/core/common/configuration_policy_provider_test.cc

Index: components/policy/core/common/configuration_policy_provider_test.cc
diff --git a/components/policy/core/common/configuration_policy_provider_test.cc b/components/policy/core/common/configuration_policy_provider_test.cc
index 9da4efa33f3d53d1fbbf679fd348be69cc8cc519..b8e5356558c959eec624c7b72ded30247e589f27 100644
--- a/components/policy/core/common/configuration_policy_provider_test.cc
+++ b/components/policy/core/common/configuration_policy_provider_test.cc
@@ -133,7 +133,12 @@ const char kKeyDictionary[] = "DictionaryPolicy";
 
 }  // namespace test_keys
 
-PolicyTestBase::PolicyTestBase() {}
+PolicyTestBase::PolicyTestBase()
+#if defined(OS_POSIX)
+    : file_descriptor_watcher_(&loop_)
+#endif
+{
+}
 
 PolicyTestBase::~PolicyTestBase() {}