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chromium/content/test/data/accessibility/aria/aria-combobox-implicit-haspopup-expected-mac.txt 

AXWebArea
++AXComboBox AXDescription='ComboBoxGrouping'
++++AXTextField
++AXComboBox AXDescription='TextFieldWithComboBox'
++AXComboBox AXDescription='ComboBoxMenuButton' AXValue='Select'
++++AXStaticText AXValue='Select'