ui: Cleanup class/struct forward declarations

ui/accessibility/ax_node.h

 // Copyright 2013 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_ACCESSIBILITY_AX_NODE_H_
 #define UI_ACCESSIBILITY_AX_NODE_H_
 
 #include <stdint.h>
 
 #include <vector>
 
 #include "ui/accessibility/ax_node_data.h"
 
-namespace gfx {
-class Rect;
-}
-
 namespace ui {
 
 // One node in an AXTree.
 class AX_EXPORT AXNode {
  public:
   // The constructor requires a parent, id, and index in parent, but
   // the data is not required. After initialization, only index_in_parent
   // is allowed to change, the others are guaranteed to never change.
   AXNode(AXNode* parent, int32_t id, int32_t index_in_parent);
   virtual ~AXNode();
@@ skipping 53 matching lines @@
 
   int index_in_parent_;
   AXNode* parent_;
   std::vector<AXNode*> children_;
   AXNodeData data_;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_NODE_H_