Convert //base to use std::unique_ptr

base/task_scheduler/task_tracker.cc

Index: base/task_scheduler/task_tracker.cc
diff --git a/base/task_scheduler/task_tracker.cc b/base/task_scheduler/task_tracker.cc
index 4f15b9e8128b5faaa7db8065193afa69058504c2..50922bbc8cf9004491bc59c1ac4d6bdbf3e1c5d3 100644
--- a/base/task_scheduler/task_tracker.cc
+++ b/base/task_scheduler/task_tracker.cc
@@ -59,8 +59,8 @@ void TaskTracker::Shutdown() {
 }
 
 void TaskTracker::PostTask(
-    const Callback<void(scoped_ptr<Task>)>& post_task_callback,
-    scoped_ptr<Task> task) {
+    const Callback<void(std::unique_ptr<Task>)>& post_task_callback,
+    std::unique_ptr<Task> task) {
   DCHECK(!post_task_callback.is_null());
   DCHECK(task);