base: Remove some unnecessary const scoped_refptr<>&.

base/memory/ref_counted_delete_on_message_loop.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_MEMORY_REF_COUNTED_DELETE_ON_MESSAGE_LOOP_H_
 #define BASE_MEMORY_REF_COUNTED_DELETE_ON_MESSAGE_LOOP_H_
 
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 
 namespace base {
 
 // RefCountedDeleteOnMessageLoop is similar to RefCountedThreadSafe, and ensures
 // that the object will be deleted on a specified message loop.
 //
 // Sample usage:
 // class Foo : public RefCountedDeleteOnMessageLoop<Foo> {
 //
-//   Foo(const scoped_refptr<SingleThreadTaskRunner>& loop)
-//       : RefCountedDeleteOnMessageLoop<Foo>(loop) {
-//     ...
-//   }
+//   Foo(scoped_refptr<SingleThreadTaskRunner> loop)
+//       : RefCountedDeleteOnMessageLoop<Foo>(std::move(loop)) {}
 //   ...
 //  private:
 //   friend class RefCountedDeleteOnMessageLoop<Foo>;
 //   friend class DeleteHelper<Foo>;
 //
 //   ~Foo();
 // };
 
 // TODO(skyostil): Rename this to RefCountedDeleteOnTaskRunner.
 template <class T>
 class RefCountedDeleteOnMessageLoop : public subtle::RefCountedThreadSafeBase {
  public:
   // This constructor will accept a MessageL00pProxy object, but new code should
   // prefer a SingleThreadTaskRunner. A SingleThreadTaskRunner for the
   // MessageLoop on the current thread can be acquired by calling
   // MessageLoop::current()->task_runner().
   RefCountedDeleteOnMessageLoop(
-      const scoped_refptr<SingleThreadTaskRunner>& task_runner)
-      : task_runner_(task_runner) {
+      scoped_refptr<SingleThreadTaskRunner> task_runner)
+      : task_runner_(std::move(task_runner)) {
     DCHECK(task_runner_);
   }
 
   void AddRef() const {
     subtle::RefCountedThreadSafeBase::AddRef();
   }
 
   void Release() const {
     if (subtle::RefCountedThreadSafeBase::Release())
       DestructOnMessageLoop();
@@ skipping 13 matching lines @@
 
   scoped_refptr<SingleThreadTaskRunner> task_runner_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RefCountedDeleteOnMessageLoop);
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_REF_COUNTED_DELETE_ON_MESSAGE_LOOP_H_