Adds Window::MoveChildToFront, with surrounding changes.

ui/gfx/compositor/layer.h

 // Copyright (c) 2011 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 UI_GFX_COMPOSITOR_LAYER_H_
 #define UI_GFX_COMPOSITOR_LAYER_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 56 matching lines @@
 
   // Adds a new Layer to this Layer.
   void Add(Layer* child);
 
   // Removes a Layer from this Layer.
   void Remove(Layer* child);
 
   // Moves a child to the end of the child list.
   void MoveToFront(Layer* child);
 
+  // Moves |child| to be above |other|. Does nothing if |other| is already above
+  // |child|.
+  void MoveAbove(Layer* child, Layer* other);
+
   // Returns the child Layers.
   const std::vector<Layer*>& children() const { return children_; }
 
   // The parent.
   const Layer* parent() const { return parent_; }
   Layer* parent() { return parent_; }
 
   // Returns true if this Layer contains |other| somewhere in its children.
   bool Contains(const Layer* other) const;
 
@@ skipping 219 matching lines @@
   WebKit::WebLayer web_layer_;
   bool web_layer_is_accelerated_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace ui
 
 #endif  // UI_GFX_COMPOSITOR_LAYER_H_