Make AXPlatformNodeDelegate::GetData() const

ui/accessibility/platform/ax_platform_node_delegate.h

Index: ui/accessibility/platform/ax_platform_node_delegate.h
diff --git a/ui/accessibility/platform/ax_platform_node_delegate.h b/ui/accessibility/platform/ax_platform_node_delegate.h
index f727fd00cc72d5d6aaf1968f4936246a4259b009..3dfe1d7f965e3448762fb8e47d5213ae9a4f0b06 100644
--- a/ui/accessibility/platform/ax_platform_node_delegate.h
+++ b/ui/accessibility/platform/ax_platform_node_delegate.h
@@ -34,7 +34,7 @@ class AX_EXPORT AXPlatformNodeDelegate {
   // 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;