Make AXPlatformNodeDelegate::GetData() const

ui/accessibility/platform/ax_platform_node_delegate.h

 // Copyright 2014 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_PLATFORM_AX_PLATFORM_NODE_DELEGATE_H_
 #define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_DELEGATE_H_
 
 #include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_export.h"
 #include "ui/gfx/geometry/vector2d.h"
@@ skipping 16 matching lines @@
 // to provide accessibility. That's why GetParent, ChildAtIndex, HitTestSync,
 // and GetFocus all return a gfx::NativeViewAccessible - so you can return a
 // native accessible if necessary, and AXPlatformNode::GetNativeViewAccessible
 // otherwise.
 class AX_EXPORT AXPlatformNodeDelegate {
  public:
   // Get the accessibility data that should be exposed for this node.
   // Virtually all of the information is obtained from this structure
   // (role, state, name, cursor position, etc.) - the rest of this interface
   // is mostly to implement support for walking the accessibility tree.
-  virtual const AXNodeData& GetData() = 0;
+  virtual const AXNodeData& GetData() const = 0;
 
   // Get the window the node is contained in.
   virtual gfx::NativeWindow GetTopLevelWidget() = 0;
 
   // Get the parent of the node, which may be an AXPlatformNode or it may
   // be a native accessible object implemented by another class.
   virtual gfx::NativeViewAccessible GetParent() = 0;
 
   // Get the number of children of this node.
   virtual int GetChildCount() = 0;
@@ skipping 38 matching lines @@
   virtual bool AccessibilityPerformAction(const ui::AXActionData& data) = 0;
 
   // Perform the default action, e.g. click a button, follow a link, or
   // toggle a checkbox.
   virtual void DoDefaultAction() = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_DELEGATE_H_