Fix PrepareTextureCopyOutputResult to avoid ScopedCallbackRunner.

base/callback_helpers.cc

 // 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.
 
 #include "base/callback_helpers.h"
 
 #include "base/callback.h"
+#include "base/logging.h"
 
 namespace base {
 
 ScopedClosureRunner::ScopedClosureRunner() {}
 
 ScopedClosureRunner::ScopedClosureRunner(const Closure& closure)
     : closure_(closure) {}
 
 ScopedClosureRunner::~ScopedClosureRunner() {
   if (!closure_.is_null())
     closure_.Run();
 }
 
 ScopedClosureRunner::ScopedClosureRunner(ScopedClosureRunner&& other)
     : closure_(other.Release()) {}
 
 ScopedClosureRunner& ScopedClosureRunner::operator=(
     ScopedClosureRunner&& other) {
-  Reset(other.Release());
+  DCHECK(closure_.is_null());
+  ReplaceClosure(other.Release());
   return *this;
 }
 
-void ScopedClosureRunner::Reset() {
+void ScopedClosureRunner::RunNow() {
   Closure old_closure = Release();
   if (!old_closure.is_null())
     old_closure.Run();
 }
 
-void ScopedClosureRunner::Reset(const Closure& closure) {
+void ScopedClosureRunner::ReplaceClosure(const Closure& closure) {
   Closure old_closure = Release();
   closure_ = closure;
   if (!old_closure.is_null())
     old_closure.Run();
 }
 
 Closure ScopedClosureRunner::Release() {
   Closure result = closure_;
   closure_.Reset();
   return result;
 }
 
 }  // namespace base