Browsing Basque translation

UNUSED: () OR (chromeos) OR (is_macosx or is_ios) == False
note: 'Action link text to undo removing a thumbnail from the most visited section.'
note: 'In the Gallery, the text on the button that reverts the most recent operation.'
note: 'Text displayed on the button to undo a theme installation and go back to the previous theme.'
note: 'Text of an Undo button.'
note: 'The Mac menu item undo in the edit menu.'
in: results/cr/chrome/app/generated_resources.grd, as IDS_THEME_INSTALL_INFOBAR_UNDO_BUTTON
in: results/cr/chrome/app/generated_resources.grd, as IDS_ONE_CLICK_BUBBLE_UNDO