style: Autogenerate StyleAppearance.

This builds on bug 1428676 and introduces StyleAppearance, which replaces the
NS_THEME_* constants.

Really sorry for the size of the patch.

There's a non-trivial change in the gtk theme, which I submitted separately as
bug 1478385.

Differential Revision: https://phabricator.services.mozilla.com/D2361

components/style/values/specified/box.rs

@@ -881,3 +881,249 @@ pub enum Clear {
     InlineStart,
     InlineEnd
 }
+
+/// The value for the `appearance` property.
+///
+/// https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-appearance
+///
+/// NOTE(emilio): When changing this you may want to regenerate the C++ bindings
+/// (see components/style/cbindgen.toml)
+#[allow(missing_docs)]
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq,
+         SpecifiedValueInfo, ToCss, ToComputedValue)]
+#[repr(u8)]
+pub enum Appearance {
+    /// No appearance at all.
+    None,
+    /// A typical dialog button.
+    Button,
+    /// Various arrows that go in buttons
+    ButtonArrowDown,
+    ButtonArrowNext,
+    ButtonArrowPrevious,
+    ButtonArrowUp,
+    /// A rectangular button that contains complex content
+    /// like images (e.g. HTML <button> elements)
+    ButtonBevel,
+    /// The focus outline box inside of a button.
+    ButtonFocus,
+    /// The caret of a text area
+    Caret,
+    /// A dual toolbar button (e.g., a Back button with a dropdown)
+    Dualbutton,
+    /// A groupbox.
+    Groupbox,
+    /// A inner-spin button.
+    InnerSpinButton,
+    /// List boxes.
+    Listbox,
+    /// A listbox item.
+    Listitem,
+    /// Menu Bar background
+    Menubar,
+    /// <menu> and <menuitem> appearances
+    Menuitem,
+    Checkmenuitem,
+    Radiomenuitem,
+    /// For text on non-iconic menuitems only
+    Menuitemtext,
+    /// A dropdown list.
+    Menulist,
+    /// The dropdown button(s) that open up a dropdown list.
+    MenulistButton,
+    /// The text part of a dropdown list, to left of button.
+    MenulistText,
+    /// An editable textfield with a dropdown list (a combobox).
+    MenulistTextfield,
+    /// Menu Popup background.
+    Menupopup,
+    /// menu checkbox/radio appearances
+    Menucheckbox,
+    Menuradio,
+    Menuseparator,
+    Menuarrow,
+    /// An image in the menu gutter, like in bookmarks or history.
+    Menuimage,
+    /// A horizontal meter bar.
+    Meterbar,
+    /// The meter bar's meter indicator.
+    Meterchunk,
+    /// For HTML's <input type=number>
+    NumberInput,
+    /// A horizontal progress bar.
+    Progressbar,
+    /// The progress bar's progress indicator
+    Progresschunk,
+    /// A vertical progress bar.
+    ProgressbarVertical,
+    /// A vertical progress chunk.
+    ProgresschunkVertical,
+    /// A checkbox element.
+    Checkbox,
+    /// A radio element within a radio group.
+    Radio,
+    /// A generic container that always repaints on state changes. This is a
+    /// hack to make XUL checkboxes and radio buttons work.
+    CheckboxContainer,
+    RadioContainer,
+    /// The label part of a checkbox or radio button, used for painting a focus
+    /// outline.
+    CheckboxLabel,
+    RadioLabel,
+    /// nsRangeFrame and its subparts
+    Range,
+    RangeThumb,
+    /// The resizer background area in a status bar for the resizer widget in
+    /// the corner of a window.
+    Resizerpanel,
+    /// The resizer itself.
+    Resizer,
+    /// A slider.
+    ScaleHorizontal,
+    ScaleVertical,
+    /// A slider's thumb.
+    ScalethumbHorizontal,
+    ScalethumbVertical,
+    /// If the platform supports it, the left/right chunks of the slider thumb.
+    Scalethumbstart,
+    Scalethumbend,
+    /// The ticks for a slider.
+    Scalethumbtick,
+    /// A scrollbar.
+    Scrollbar,
+    /// A small scrollbar.
+    ScrollbarSmall,
+    /// The scrollbar slider
+    ScrollbarHorizontal,
+    ScrollbarVertical,
+    /// A scrollbar button (up/down/left/right).
+    /// Keep these in order (some code casts these values to `int` in order to
+    /// compare them against each other).
+    ScrollbarbuttonDown,
+    ScrollbarbuttonLeft,
+    ScrollbarbuttonRight,
+    ScrollbarbuttonUp,
+    /// The scrollbar thumb.
+    ScrollbarthumbHorizontal,
+    ScrollbarthumbVertical,
+    /// The scrollbar track.
+    ScrollbartrackHorizontal,
+    ScrollbartrackVertical,
+    /// The scroll corner
+    Scrollcorner,
+    /// A searchfield.
+    Searchfield,
+    /// A separator.  Can be horizontal or vertical.
+    Separator,
+    /// A spin control (up/down control for time/date pickers).
+    Spinner,
+    /// The up button of a spin control.
+    SpinnerUpbutton,
+    /// The down button of a spin control.
+    SpinnerDownbutton,
+    /// The textfield of a spin control
+    SpinnerTextfield,
+    /// A splitter.  Can be horizontal or vertical.
+    Splitter,
+    /// A status bar in a main application window.
+    Statusbar,
+    /// A single pane of a status bar.
+    Statusbarpanel,
+    /// A single tab in a tab widget.
+    Tab,
+    /// A single pane (inside the tabpanels container).
+    Tabpanel,
+    /// The tab panels container.
+    Tabpanels,
+    /// The tabs scroll arrows (left/right).
+    TabScrollArrowBack,
+    TabScrollArrowForward,
+    /// A textfield or text area.
+    Textfield,
+    /// A multiline text field.
+    TextfieldMultiline,
+    /// A toolbar in an application window.
+    Toolbar,
+    /// A single toolbar button (with no associated dropdown).
+    Toolbarbutton,
+    /// The dropdown portion of a toolbar button
+    ToolbarbuttonDropdown,
+    /// The gripper for a toolbar.
+    Toolbargripper,
+    /// The toolbox that contains the toolbars.
+    Toolbox,
+    /// A tooltip.
+    Tooltip,
+    /// A listbox or tree widget header
+    Treeheader,
+    /// An individual header cell
+    Treeheadercell,
+    /// The sort arrow for a header.
+    Treeheadersortarrow,
+    /// A tree item.
+    Treeitem,
+    /// A tree widget branch line
+    Treeline,
+    /// A tree widget twisty.
+    Treetwisty,
+    /// Open tree widget twisty.
+    Treetwistyopen,
+    /// A tree widget.
+    Treeview,
+    /// Window and dialog backgrounds.
+    Window,
+    Dialog,
+
+    /// Vista Rebars.
+    MozWinCommunicationsToolbox,
+    MozWinMediaToolbox,
+    MozWinBrowsertabbarToolbox,
+    /// Vista glass.
+    MozWinGlass,
+    MozWinBorderlessGlass,
+    /// -moz-apperance style used in setting proper glass margins.
+    MozWinExcludeGlass,
+
+    /// Titlebar elements on the Mac.
+    MozMacFullscreenButton,
+    /// Mac help button.
+    MozMacHelpButton,
+
+    /// Windows themed window frame elements.
+    MozWindowButtonBox,
+    MozWindowButtonBoxMaximized,
+    MozWindowButtonClose,
+    MozWindowButtonMaximize,
+    MozWindowButtonMinimize,
+    MozWindowButtonRestore,
+    MozWindowFrameBottom,
+    MozWindowFrameLeft,
+    MozWindowFrameRight,
+    MozWindowTitlebar,
+    MozWindowTitlebarMaximized,
+
+    MozGtkInfoBar,
+    MozMacActiveSourceListSelection,
+    MozMacDisclosureButtonClosed,
+    MozMacDisclosureButtonOpen,
+    MozMacSourceList,
+    MozMacSourceListSelection,
+    MozMacVibrancyDark,
+    MozMacVibrancyLight,
+    MozMacVibrantTitlebarDark,
+    MozMacVibrantTitlebarLight,
+
+    /// A non-disappearing scrollbar.
+    #[css(skip)]
+    ScrollbarNonDisappearing,
+
+    /// A themed focus outline (for outline:auto).
+    ///
+    /// This isn't exposed to CSS at all, just here for convenience.
+    #[css(skip)]
+    FocusOutline,
+
+    /// A dummy variant that should be last to let the GTK widget do hackery.
+    #[css(skip)]
+    Count,
+}