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

base/debug/activity_tracker_unittest.cc

Index: base/debug/activity_tracker_unittest.cc
diff --git a/base/debug/activity_tracker_unittest.cc b/base/debug/activity_tracker_unittest.cc
index c7efa580e8857586c43ef90b481e383a86b83595..4271d11337d3afc4d4a282e6874de2d92dc075be 100644
--- a/base/debug/activity_tracker_unittest.cc
+++ b/base/debug/activity_tracker_unittest.cc
@@ -216,7 +216,7 @@ TEST_F(ActivityTrackerTest, ScopedTaskTest) {
   ASSERT_EQ(0U, snapshot.activity_stack.size());
 
   {
-    PendingTask task1(FROM_HERE, base::Bind(&DoNothing));
+    PendingTask task1(FROM_HERE, base::BindOnce(&DoNothing));
     ScopedTaskRunActivity activity1(task1);
     ActivityUserData& user_data1 = activity1.user_data();
     (void)user_data1;  // Tell compiler it's been used.
@@ -227,7 +227,7 @@ TEST_F(ActivityTrackerTest, ScopedTaskTest) {
     EXPECT_EQ(Activity::ACT_TASK, snapshot.activity_stack[0].activity_type);
 
     {
-      PendingTask task2(FROM_HERE, base::Bind(&DoNothing));
+      PendingTask task2(FROM_HERE, base::BindOnce(&DoNothing));
       ScopedTaskRunActivity activity2(task2);
       ActivityUserData& user_data2 = activity2.user_data();
       (void)user_data2;  // Tell compiler it's been used.
@@ -413,7 +413,7 @@ TEST_F(ActivityTrackerTest, ProcessDeathTest) {
   global->RecordProcessLaunch(other_process_id, FILE_PATH_LITERAL("foo --bar"));
 
   // Do some activities.
-  PendingTask task(FROM_HERE, base::Bind(&DoNothing));
+  PendingTask task(FROM_HERE, base::BindOnce(&DoNothing));
   ScopedTaskRunActivity activity(task);
   ActivityUserData& user_data = activity.user_data();
   ASSERT_NE(0U, user_data.id());