Pass Callback to TaskRunner by value and consume it on invocation (1)

base/threading/sequenced_worker_pool.h

Index: base/threading/sequenced_worker_pool.h
diff --git a/base/threading/sequenced_worker_pool.h b/base/threading/sequenced_worker_pool.h
index 0d42de9138e39e839e7fcfda892901d1bb0e1eb3..8cdeb0b5dbcc7aa799f6a52335096db156e0f02c 100644
--- a/base/threading/sequenced_worker_pool.h
+++ b/base/threading/sequenced_worker_pool.h
@@ -12,7 +12,7 @@
 #include <string>
 
 #include "base/base_export.h"
-#include "base/callback_forward.h"
+#include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
@@ -275,8 +275,7 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   //
   // Returns true if the task was posted successfully. This may fail during
   // shutdown regardless of the specified ShutdownBehavior.
-  bool PostWorkerTask(const tracked_objects::Location& from_here,
-                      const Closure& task);
+  bool PostWorkerTask(const tracked_objects::Location& from_here, Closure task);
 
   // Same as PostWorkerTask but allows a delay to be specified (although doing
   // so changes the shutdown behavior). The task will be run after the given
@@ -288,13 +287,13 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   // task will be guaranteed to run to completion before shutdown
   // (BLOCK_SHUTDOWN semantics).
   bool PostDelayedWorkerTask(const tracked_objects::Location& from_here,
-                             const Closure& task,
+                             Closure task,
                              TimeDelta delay);
 
   // Same as PostWorkerTask but allows specification of the shutdown behavior.
   bool PostWorkerTaskWithShutdownBehavior(
       const tracked_objects::Location& from_here,
-      const Closure& task,
+      Closure task,
       WorkerShutdown shutdown_behavior);
 
   // Like PostWorkerTask above, but provides sequencing semantics. This means
@@ -310,13 +309,13 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   // shutdown regardless of the specified ShutdownBehavior.
   bool PostSequencedWorkerTask(SequenceToken sequence_token,
                                const tracked_objects::Location& from_here,
-                               const Closure& task);
+                               Closure task);
 
   // Like PostSequencedWorkerTask above, but allows you to specify a named
   // token, which saves an extra call to GetNamedSequenceToken.
   bool PostNamedSequencedWorkerTask(const std::string& token_name,
                                     const tracked_objects::Location& from_here,
-                                    const Closure& task);
+                                    Closure task);
 
   // Same as PostSequencedWorkerTask but allows a delay to be specified
   // (although doing so changes the shutdown behavior). The task will be run
@@ -330,7 +329,7 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   bool PostDelayedSequencedWorkerTask(
       SequenceToken sequence_token,
       const tracked_objects::Location& from_here,
-      const Closure& task,
+      Closure task,
       TimeDelta delay);
 
   // Same as PostSequencedWorkerTask but allows specification of the shutdown
@@ -338,12 +337,12 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   bool PostSequencedWorkerTaskWithShutdownBehavior(
       SequenceToken sequence_token,
       const tracked_objects::Location& from_here,
-      const Closure& task,
+      Closure task,
       WorkerShutdown shutdown_behavior);
 
   // TaskRunner implementation. Forwards to PostDelayedWorkerTask().
   bool PostDelayedTask(const tracked_objects::Location& from_here,
-                       const Closure& task,
+                       Closure task,
                        TimeDelta delay) override;
   bool RunsTasksOnCurrentThread() const override;