Rewrite base::Bind into base::BindOnce on trivial cases in base

base/message_loop/message_pump_libevent_unittest.cc

Index: base/message_loop/message_pump_libevent_unittest.cc
diff --git a/base/message_loop/message_pump_libevent_unittest.cc b/base/message_loop/message_pump_libevent_unittest.cc
index 3e7a200a2352a9a9ea37a6347f84b95781a2bbce..0a7c485561682c5923b03376acf9bc345d68e918 100644
--- a/base/message_loop/message_pump_libevent_unittest.cc
+++ b/base/message_loop/message_pump_libevent_unittest.cc
@@ -187,7 +187,7 @@ class NestedPumpWatcher : public MessagePumpLibevent::Watcher {
   void OnFileCanReadWithoutBlocking(int /* fd */) override {
     RunLoop runloop;
     ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, Bind(&QuitMessageLoopAndStart, runloop.QuitClosure()));
+        FROM_HERE, BindOnce(&QuitMessageLoopAndStart, runloop.QuitClosure()));
     runloop.Run();
   }
 
@@ -218,7 +218,7 @@ class QuitWatcher : public BaseWatcher {
 
   void OnFileCanReadWithoutBlocking(int /* fd */) override {
     // Post a fatal closure to the MessageLoop before we quit it.
-    ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, Bind(&FatalClosure));
+    ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, BindOnce(&FatalClosure));
 
     // Now quit the MessageLoop.
     run_loop_->Quit();
@@ -259,12 +259,12 @@ TEST_F(MessagePumpLibeventTest, QuitWatcher) {
   const WaitableEventWatcher::EventCallback write_fd_task =
       Bind(&WriteFDWrapper, pipefds_[1], &buf, 1);
   io_loop()->task_runner()->PostTask(
-      FROM_HERE, Bind(IgnoreResult(&WaitableEventWatcher::StartWatching),
-                      Unretained(watcher.get()), &event, write_fd_task));
+      FROM_HERE, BindOnce(IgnoreResult(&WaitableEventWatcher::StartWatching),
+                          Unretained(watcher.get()), &event, write_fd_task));
 
   // Queue |event| to signal on |loop|.
   loop.task_runner()->PostTask(
-      FROM_HERE, Bind(&WaitableEvent::Signal, Unretained(&event)));
+      FROM_HERE, BindOnce(&WaitableEvent::Signal, Unretained(&event)));
 
   // Now run the MessageLoop.
   run_loop.Run();
@@ -272,7 +272,7 @@ TEST_F(MessagePumpLibeventTest, QuitWatcher) {
   // StartWatching can move |watcher| to IO thread. Release on IO thread.
   io_loop()->task_runner()->PostTask(
       FROM_HERE,
-      Bind(&WaitableEventWatcher::StopWatching, Owned(watcher.release())));
+      BindOnce(&WaitableEventWatcher::StopWatching, Owned(watcher.release())));
 }
 
 }  // namespace