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

ui/base/models/tree_model.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_MODELS_TREE_MODEL_H_
 #define UI_BASE_MODELS_TREE_MODEL_H_
 #pragma once
 
 #include <vector>
 
 #include "base/string16.h"
+#include "ui/ui_api.h"
 
 class SkBitmap;
 
 namespace ui {
 
 class TreeModel;
 
 // TreeModelNode --------------------------------------------------------------
 
 // Type of class returned from the model.
@@ skipping 24 matching lines @@
   // Notification that the contents of a node has changed.
   virtual void TreeNodeChanged(TreeModel* model, TreeModelNode* node) = 0;
 
  protected:
   virtual ~TreeModelObserver() {}
 };
 
 // TreeModel ------------------------------------------------------------------
 
 // The model for TreeView.
-class TreeModel {
+class UI_API TreeModel {
  public:
   // Returns the root of the tree. This may or may not be shown in the tree,
   // see SetRootShown for details.
   virtual TreeModelNode* GetRoot() = 0;
 
   // Returns the number of children in |parent|.
   virtual int GetChildCount(TreeModelNode* parent) = 0;
 
   // Returns the child node of |parent| at |index|.
   virtual TreeModelNode* GetChild(TreeModelNode* parent, int index) = 0;
@@ skipping 23 matching lines @@
   // GetIcons.
   virtual int GetIconIndex(TreeModelNode* node);
 
  protected:
   virtual ~TreeModel() {}
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_MODELS_TREE_MODEL_H_