Add more out of line copy ctors for complex classes.

ui/base/ime/composition_text.h

 // Copyright (c) 2012 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_BASE_IME_COMPOSITION_TEXT_H_
 #define UI_BASE_IME_COMPOSITION_TEXT_H_
 
 #include <stddef.h>
 
 #include "base/strings/string16.h"
 #include "ui/base/ime/composition_underline.h"
 #include "ui/base/ime/ui_base_ime_export.h"
 #include "ui/gfx/range/range.h"
 
 namespace ui {
 
 // A struct represents the status of an ongoing composition text.
 struct UI_BASE_IME_EXPORT CompositionText {
   CompositionText();
+  CompositionText(const CompositionText& other);
   ~CompositionText();
 
   bool operator==(const CompositionText& rhs) const {
     if ((this->text != rhs.text) ||
         (this->selection != rhs.selection) ||
         (this->underlines.size() != rhs.underlines.size()))
       return false;
     for (size_t i = 0; i < this->underlines.size(); ++i) {
       if (this->underlines[i] != rhs.underlines[i])
         return false;
@@ skipping 20 matching lines @@
   // Selection range in the composition text. It represents the caret position
   // if the range length is zero. Usually it's used for representing the target
   // clause (on Windows). Gtk doesn't have such concept, so background color is
   // usually used instead.
   gfx::Range selection;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_IME_COMPOSITION_TEXT_H_