cc: Change scoped_ptr<T>() to nullptr.

cc/layers/texture_layer.cc

 // Copyright 2010 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 "cc/layers/texture_layer.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/synchronization/lock.h"
@@ skipping 33 matching lines @@
 
 void TextureLayer::ClearClient() {
   if (rate_limit_context_ && client_ && layer_tree_host())
     layer_tree_host()->StopRateLimiter();
   client_ = nullptr;
   ClearTexture();
   UpdateDrawsContent(HasDrawableContent());
 }
 
 void TextureLayer::ClearTexture() {
-  SetTextureMailbox(TextureMailbox(), scoped_ptr<SingleReleaseCallback>());
+  SetTextureMailbox(TextureMailbox(), nullptr);
 }
 
 scoped_ptr<LayerImpl> TextureLayer::CreateLayerImpl(LayerTreeImpl* tree_impl) {
   return TextureLayerImpl::Create(tree_impl, id());
 }
 
 void TextureLayer::SetFlipped(bool flipped) {
   if (flipped_ == flipped)
     return;
   flipped_ = flipped;
@@ skipping 268 matching lines @@
 void TextureLayer::TextureMailboxHolder::ReturnAndReleaseOnImplThread(
     uint32 sync_point,
     bool is_lost,
     BlockingTaskRunner* main_thread_task_runner) {
   Return(sync_point, is_lost);
   main_thread_task_runner->PostTask(
       FROM_HERE, base::Bind(&TextureMailboxHolder::InternalRelease, this));
 }
 
 }  // namespace cc