ui: Add out-of-line copy ctors for complex classes.

ui/gl/gl_surface_overlay.h

 // Copyright 2015 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_GL_GL_SURFACE_OVERLAY_H_
 #define UI_GL_GL_SURFACE_OVERLAY_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/overlay_transform.h"
 #include "ui/gl/gl_image.h"
 
 namespace gfx {
 
 // For saving the properties of a GLImage overlay plane and scheduling it later.
 class GLSurfaceOverlay {
  public:
   GLSurfaceOverlay(int z_order,
                    OverlayTransform transform,
                    gl::GLImage* image,
                    const Rect& bounds_rect,
                    const RectF& crop_rect);
+  GLSurfaceOverlay(const GLSurfaceOverlay& other);
   ~GLSurfaceOverlay();
 
   // Schedule the image as an overlay plane to be shown at swap time for
   // |widget|.
   bool ScheduleOverlayPlane(AcceleratedWidget widget) const;
 
  private:
   int z_order_;
   OverlayTransform transform_;
   scoped_refptr<gl::GLImage> image_;
   Rect bounds_rect_;
   RectF crop_rect_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_SURFACE_OVERLAY_H_