Use container::back() and container::pop_back().

cc/trees/property_tree.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_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 67 matching lines @@
   }
   const T* Node(int i) const {
     // TODO(vollick): remove this.
     CHECK(i < static_cast<int>(nodes_.size()));
     return i > -1 ? &nodes_[i] : nullptr;
   }
 
   T* parent(const T* t) { return Node(t->parent_id); }
   const T* parent(const T* t) const { return Node(t->parent_id); }
 
-  T* back() { return size() ? &nodes_[nodes_.size() - 1] : nullptr; }
-  const T* back() const {
-    return size() ? &nodes_[nodes_.size() - 1] : nullptr;
-  }
+  T* back() { return size() ? &nodes_.back() : nullptr; }
+  const T* back() const { return size() ? &nodes_.back() : nullptr; }
 
   void clear();
   size_t size() const { return nodes_.size(); }
 
   void set_needs_update(bool needs_update) { needs_update_ = needs_update; }
   bool needs_update() const { return needs_update_; }
 
   std::vector<T>& nodes() { return nodes_; }
   const std::vector<T>& nodes() const { return nodes_; }
 
@@ skipping 468 matching lines @@
   gfx::Vector2dF inner_viewport_container_bounds_delta_;
   gfx::Vector2dF outer_viewport_container_bounds_delta_;
   gfx::Vector2dF inner_viewport_scroll_bounds_delta_;
 
   PropertyTreesCachedData cached_data_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_