Support PostTaskAndReply from a sequenced task.

base/task_runner.cc

Index: base/task_runner.cc
diff --git a/base/task_runner.cc b/base/task_runner.cc
index 262e1f8b09eac8d9f91b4113ddeccc27a33323ad..6c6b76e6318eac6a0cf93bb90a31fd135137e923 100644
--- a/base/task_runner.cc
+++ b/base/task_runner.cc
@@ -4,42 +4,13 @@
 
 #include "base/task_runner.h"
 
+#include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/threading/post_task_and_reply_impl.h"
 
 namespace base {
 
-namespace {
-
-// TODO(akalin): There's only one other implementation of
-// PostTaskAndReplyImpl in WorkerPool.  Investigate whether it'll be
-// possible to merge the two.
-class PostTaskAndReplyTaskRunner : public internal::PostTaskAndReplyImpl {
- public:
-  explicit PostTaskAndReplyTaskRunner(TaskRunner* destination);
-
- private:
-  bool PostTask(const tracked_objects::Location& from_here,
-                const Closure& task) override;
-
-  // Non-owning.
-  TaskRunner* destination_;
-};
-
-PostTaskAndReplyTaskRunner::PostTaskAndReplyTaskRunner(
-    TaskRunner* destination) : destination_(destination) {
-  DCHECK(destination_);
-}
-
-bool PostTaskAndReplyTaskRunner::PostTask(
-    const tracked_objects::Location& from_here,
-    const Closure& task) {
-  return destination_->PostTask(from_here, task);
-}
-
-}  // namespace
-
 bool TaskRunner::PostTask(const tracked_objects::Location& from_here,
                           const Closure& task) {
   return PostDelayedTask(from_here, task, base::TimeDelta());
@@ -49,8 +20,8 @@ bool TaskRunner::PostTaskAndReply(
     const tracked_objects::Location& from_here,
     const Closure& task,
     const Closure& reply) {
-  return PostTaskAndReplyTaskRunner(this).PostTaskAndReply(
-      from_here, task, reply);
+  return internal::PostTaskAndReply(
+      from_here, task, reply, Bind(&TaskRunner::PostTask, Unretained(this)));
 }
 
 TaskRunner::TaskRunner() {}