Introduce ui.dll / libui.so for the component build.

ui/base/ime/composition_text.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_BASE_IME_COMPOSITION_TEXT_H_
 #define UI_BASE_IME_COMPOSITION_TEXT_H_
 #pragma once
 
 #include "base/string16.h"
 #include "ui/base/ime/composition_underline.h"
 #include "ui/base/range/range.h"
+#include "ui/base/ui_base_api.h"
 
 namespace ui {
 
 // A struct represents the status of an ongoing composition text.
-struct CompositionText {
+struct UI_BASE_API CompositionText {
   CompositionText();
   ~CompositionText();
 
   void Clear();
 
   // Content of the composition text.
   string16 text;
 
   // Underline information of the composition text.
   // They must be sorted in ascending order by their start_offset and cannot be
   // overlapped with each other.
   CompositionUnderlines underlines;
 
   // 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.
   Range selection;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_IME_COMPOSITION_TEXT_H_