Change ListContainer::AppendByMoving to return a pointer to the new item

cc/base/list_container.h

 // Copyright 2014 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 CC_BASE_LIST_CONTAINER_H_
 #define CC_BASE_LIST_CONTAINER_H_
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 278 matching lines @@
   }
 
   template <typename DerivedElementType>
   void swap(ListContainer<DerivedElementType>& other) {
     data_.swap(other.data_);
   }
 
   // Appends a new item without copying. The original item will not be
   // destructed and will be replaced with a new DerivedElementType. The
   // DerivedElementType does not have to match the moved type as a full block
-  // of memory will be moved (up to MaxSizeForDerivedClass()).
+  // of memory will be moved (up to MaxSizeForDerivedClass()). A pointer to
+  // the moved element is returned.
   template <typename DerivedElementType>
-  void AppendByMoving(DerivedElementType* item) {
+  DerivedElementType* AppendByMoving(DerivedElementType* item) {
     size_t max_size_for_derived_class = MaxSizeForDerivedClass();
     void* new_item = Allocate(max_size_for_derived_class);
     memcpy(new_item, static_cast<void*>(item), max_size_for_derived_class);
     // Construct a new element in-place so it can be destructed safely.
     new (item) DerivedElementType;
+    return static_cast<DerivedElementType*>(new_item);
   }
 
   using ListContainerBase::size;
   using ListContainerBase::empty;
 
   void clear() {
     for (Iterator i = begin(); i != end(); ++i) {
       i->~BaseElementType();
     }
     ListContainerBase::clear();
@@ skipping 152 matching lines @@
         ListContainerBase::ConstReverseIterator base_iterator)
         : ListContainerBase::ConstReverseIterator(base_iterator) {}
     friend ConstReverseIterator ListContainer<BaseElementType>::crbegin() const;
     friend ConstReverseIterator ListContainer<BaseElementType>::crend() const;
   };
 };
 
 }  // namespace cc
 
 #endif  // CC_BASE_LIST_CONTAINER_H_