Auto merge of #15974 - Manishearth:stylo-system-colors, r=heycam

stylo: Support system colors

r=heycam from https://bugzilla.mozilla.org/show_bug.cgi?id=1340696

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7 files changed, 720 insertions, 1 deletions

diff --git a/components/style/build_gecko.rs b/components/style/build_gecko.rs
index 6f262728954..8dbbc7f749b 100644
--- a/components/style/build_gecko.rs
+++ b/components/style/build_gecko.rs
@@ -268,6 +268,7 @@ mod bindings {
             .include(add_include("mozilla/ServoElementSnapshot.h"))
             .include(add_include("mozilla/dom/Element.h"))
             .include(add_include("mozilla/dom/NameSpaceConstants.h"))
+            .include(add_include("mozilla/LookAndFeel.h"))
             .include(add_include("mozilla/ServoBindings.h"))
             .include(add_include("nsMediaFeatures.h"))
             .include(add_include("nsMediaList.h"))
@@ -304,6 +305,7 @@ mod bindings {
             "mozilla::TraversalRootBehavior",
             "mozilla::StyleShapeRadius",
             "mozilla::StyleGrid.*",
+            "mozilla::LookAndFeel",
             ".*ThreadSafe.*Holder",
             "AnonymousContent",
             "AudioContext",
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index ff8040f140f..0859b42a943 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -975,6 +975,12 @@ extern "C" {
     pub fn Gecko_GetMediaFeatures() -> *const nsMediaFeature;
 }
 extern "C" {
+    pub fn Gecko_GetLookAndFeelSystemColor(color_id: i32,
+                                           pres_context:
+                                               RawGeckoPresContextBorrowed)
+     -> nscolor;
+}
+extern "C" {
     pub fn Gecko_Construct_Default_nsStyleFont(ptr: *mut nsStyleFont,
                                                pres_context:
                                                    RawGeckoPresContextBorrowed);
diff --git a/components/style/gecko_bindings/structs_debug.rs b/components/style/gecko_bindings/structs_debug.rs
index ef36ae06638..a91037fa567 100644
--- a/components/style/gecko_bindings/structs_debug.rs
+++ b/components/style/gecko_bindings/structs_debug.rs
@@ -7483,6 +7483,288 @@ pub mod root {
         #[derive(Debug, Copy, Clone)]
         pub struct ContainerLayerParameters([u8; 0]);
         #[repr(C)]
+        #[derive(Debug, Copy)]
+        pub struct LookAndFeel {
+            pub _address: u8,
+        }
+        #[repr(u8)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_ColorID {
+            eColorID_WindowBackground = 0,
+            eColorID_WindowForeground = 1,
+            eColorID_WidgetBackground = 2,
+            eColorID_WidgetForeground = 3,
+            eColorID_WidgetSelectBackground = 4,
+            eColorID_WidgetSelectForeground = 5,
+            eColorID_Widget3DHighlight = 6,
+            eColorID_Widget3DShadow = 7,
+            eColorID_TextBackground = 8,
+            eColorID_TextForeground = 9,
+            eColorID_TextSelectBackground = 10,
+            eColorID_TextSelectForeground = 11,
+            eColorID_TextSelectForegroundCustom = 12,
+            eColorID_TextSelectBackgroundDisabled = 13,
+            eColorID_TextSelectBackgroundAttention = 14,
+            eColorID_TextHighlightBackground = 15,
+            eColorID_TextHighlightForeground = 16,
+            eColorID_IMERawInputBackground = 17,
+            eColorID_IMERawInputForeground = 18,
+            eColorID_IMERawInputUnderline = 19,
+            eColorID_IMESelectedRawTextBackground = 20,
+            eColorID_IMESelectedRawTextForeground = 21,
+            eColorID_IMESelectedRawTextUnderline = 22,
+            eColorID_IMEConvertedTextBackground = 23,
+            eColorID_IMEConvertedTextForeground = 24,
+            eColorID_IMEConvertedTextUnderline = 25,
+            eColorID_IMESelectedConvertedTextBackground = 26,
+            eColorID_IMESelectedConvertedTextForeground = 27,
+            eColorID_IMESelectedConvertedTextUnderline = 28,
+            eColorID_SpellCheckerUnderline = 29,
+            eColorID_activeborder = 30,
+            eColorID_activecaption = 31,
+            eColorID_appworkspace = 32,
+            eColorID_background = 33,
+            eColorID_buttonface = 34,
+            eColorID_buttonhighlight = 35,
+            eColorID_buttonshadow = 36,
+            eColorID_buttontext = 37,
+            eColorID_captiontext = 38,
+            eColorID_graytext = 39,
+            eColorID_highlight = 40,
+            eColorID_highlighttext = 41,
+            eColorID_inactiveborder = 42,
+            eColorID_inactivecaption = 43,
+            eColorID_inactivecaptiontext = 44,
+            eColorID_infobackground = 45,
+            eColorID_infotext = 46,
+            eColorID_menu = 47,
+            eColorID_menutext = 48,
+            eColorID_scrollbar = 49,
+            eColorID_threeddarkshadow = 50,
+            eColorID_threedface = 51,
+            eColorID_threedhighlight = 52,
+            eColorID_threedlightshadow = 53,
+            eColorID_threedshadow = 54,
+            eColorID_window = 55,
+            eColorID_windowframe = 56,
+            eColorID_windowtext = 57,
+            eColorID__moz_buttondefault = 58,
+            eColorID__moz_field = 59,
+            eColorID__moz_fieldtext = 60,
+            eColorID__moz_dialog = 61,
+            eColorID__moz_dialogtext = 62,
+            eColorID__moz_dragtargetzone = 63,
+            eColorID__moz_cellhighlight = 64,
+            eColorID__moz_cellhighlighttext = 65,
+            eColorID__moz_html_cellhighlight = 66,
+            eColorID__moz_html_cellhighlighttext = 67,
+            eColorID__moz_buttonhoverface = 68,
+            eColorID__moz_buttonhovertext = 69,
+            eColorID__moz_menuhover = 70,
+            eColorID__moz_menuhovertext = 71,
+            eColorID__moz_menubartext = 72,
+            eColorID__moz_menubarhovertext = 73,
+            eColorID__moz_eventreerow = 74,
+            eColorID__moz_oddtreerow = 75,
+            eColorID__moz_mac_buttonactivetext = 76,
+            eColorID__moz_mac_chrome_active = 77,
+            eColorID__moz_mac_chrome_inactive = 78,
+            eColorID__moz_mac_defaultbuttontext = 79,
+            eColorID__moz_mac_focusring = 80,
+            eColorID__moz_mac_menuselect = 81,
+            eColorID__moz_mac_menushadow = 82,
+            eColorID__moz_mac_menutextdisable = 83,
+            eColorID__moz_mac_menutextselect = 84,
+            eColorID__moz_mac_disabledtoolbartext = 85,
+            eColorID__moz_mac_secondaryhighlight = 86,
+            eColorID__moz_win_mediatext = 87,
+            eColorID__moz_win_communicationstext = 88,
+            eColorID__moz_nativehyperlinktext = 89,
+            eColorID__moz_comboboxtext = 90,
+            eColorID__moz_combobox = 91,
+            eColorID__moz_gtk_info_bar_text = 92,
+            eColorID_LAST_COLOR = 93,
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_IntID {
+            eIntID_CaretBlinkTime = 0,
+            eIntID_CaretWidth = 1,
+            eIntID_ShowCaretDuringSelection = 2,
+            eIntID_SelectTextfieldsOnKeyFocus = 3,
+            eIntID_SubmenuDelay = 4,
+            eIntID_MenusCanOverlapOSBar = 5,
+            eIntID_UseOverlayScrollbars = 6,
+            eIntID_AllowOverlayScrollbarsOverlap = 7,
+            eIntID_ShowHideScrollbars = 8,
+            eIntID_SkipNavigatingDisabledMenuItem = 9,
+            eIntID_DragThresholdX = 10,
+            eIntID_DragThresholdY = 11,
+            eIntID_UseAccessibilityTheme = 12,
+            eIntID_ScrollArrowStyle = 13,
+            eIntID_ScrollSliderStyle = 14,
+            eIntID_ScrollButtonLeftMouseButtonAction = 15,
+            eIntID_ScrollButtonMiddleMouseButtonAction = 16,
+            eIntID_ScrollButtonRightMouseButtonAction = 17,
+            eIntID_TreeOpenDelay = 18,
+            eIntID_TreeCloseDelay = 19,
+            eIntID_TreeLazyScrollDelay = 20,
+            eIntID_TreeScrollDelay = 21,
+            eIntID_TreeScrollLinesMax = 22,
+            eIntID_TabFocusModel = 23,
+            eIntID_ChosenMenuItemsShouldBlink = 24,
+            eIntID_WindowsDefaultTheme = 25,
+            eIntID_DWMCompositor = 26,
+            eIntID_WindowsClassic = 27,
+            eIntID_WindowsGlass = 28,
+            eIntID_TouchEnabled = 29,
+            eIntID_MacGraphiteTheme = 30,
+            eIntID_MacYosemiteTheme = 31,
+            eIntID_AlertNotificationOrigin = 32,
+            eIntID_ScrollToClick = 33,
+            eIntID_IMERawInputUnderlineStyle = 34,
+            eIntID_IMESelectedRawTextUnderlineStyle = 35,
+            eIntID_IMEConvertedTextUnderlineStyle = 36,
+            eIntID_IMESelectedConvertedTextUnderline = 37,
+            eIntID_SpellCheckerUnderlineStyle = 38,
+            eIntID_MenuBarDrag = 39,
+            eIntID_WindowsThemeIdentifier = 40,
+            eIntID_OperatingSystemVersionIdentifier = 41,
+            eIntID_ScrollbarButtonAutoRepeatBehavior = 42,
+            eIntID_TooltipDelay = 43,
+            eIntID_SwipeAnimationEnabled = 44,
+            eIntID_ColorPickerAvailable = 45,
+            eIntID_PhysicalHomeButton = 46,
+            eIntID_ScrollbarDisplayOnMouseMove = 47,
+            eIntID_ScrollbarFadeBeginDelay = 48,
+            eIntID_ScrollbarFadeDuration = 49,
+            eIntID_ContextMenuOffsetVertical = 50,
+            eIntID_ContextMenuOffsetHorizontal = 51,
+        }
+        #[repr(u32)]
+        /**
+   * Windows themes we currently detect.
+   */
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_WindowsTheme {
+            eWindowsTheme_Generic = 0,
+            eWindowsTheme_Classic = 1,
+            eWindowsTheme_Aero = 2,
+            eWindowsTheme_LunaBlue = 3,
+            eWindowsTheme_LunaOlive = 4,
+            eWindowsTheme_LunaSilver = 5,
+            eWindowsTheme_Royale = 6,
+            eWindowsTheme_Zune = 7,
+            eWindowsTheme_AeroLite = 8,
+        }
+        #[repr(u32)]
+        /**
+   * Operating system versions.
+   */
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_OperatingSystemVersion {
+            eOperatingSystemVersion_Windows7 = 2,
+            eOperatingSystemVersion_Windows8 = 3,
+            eOperatingSystemVersion_Windows10 = 4,
+            eOperatingSystemVersion_Unknown = 5,
+        }
+        pub const LookAndFeel_eScrollArrow_None:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_None;
+        pub const LookAndFeel_eScrollArrow_StartBackward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_StartBackward;
+        pub const LookAndFeel_eScrollArrow_StartForward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_StartForward;
+        pub const LookAndFeel_eScrollArrow_EndBackward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_EndBackward;
+        pub const LookAndFeel_eScrollArrow_EndForward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_EndForward;
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel__bindgen_ty_1 {
+            eScrollArrow_None = 0,
+            eScrollArrow_StartBackward = 4096,
+            eScrollArrow_StartForward = 256,
+            eScrollArrow_EndBackward = 16,
+            eScrollArrow_EndForward = 1,
+        }
+        pub const LookAndFeel_eScrollArrowStyle_Single:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_Single;
+        pub const LookAndFeel_eScrollArrowStyle_BothAtBottom:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_BothAtBottom;
+        pub const LookAndFeel_eScrollArrowStyle_BothAtEachEnd:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_BothAtEachEnd;
+        pub const LookAndFeel_eScrollArrowStyle_BothAtTop:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_BothAtTop;
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel__bindgen_ty_2 {
+            eScrollArrowStyle_Single = 4097,
+            eScrollArrowStyle_BothAtBottom = 17,
+            eScrollArrowStyle_BothAtEachEnd = 4369,
+            eScrollArrowStyle_BothAtTop = 4352,
+        }
+        pub const LookAndFeel_eScrollThumbStyle_Normal:
+                  root::mozilla::LookAndFeel__bindgen_ty_3 =
+            LookAndFeel__bindgen_ty_3::eScrollThumbStyle_Normal;
+        pub const LookAndFeel_eScrollThumbStyle_Proportional:
+                  root::mozilla::LookAndFeel__bindgen_ty_3 =
+            LookAndFeel__bindgen_ty_3::eScrollThumbStyle_Proportional;
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel__bindgen_ty_3 {
+            eScrollThumbStyle_Normal = 0,
+            eScrollThumbStyle_Proportional = 1,
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_FloatID {
+            eFloatID_IMEUnderlineRelativeSize = 0,
+            eFloatID_SpellCheckerUnderlineRelativeSize = 1,
+            eFloatID_CaretAspectRatio = 2,
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_FontID {
+            eFont_Caption = 1,
+            eFont_Icon = 2,
+            eFont_Menu = 3,
+            eFont_MessageBox = 4,
+            eFont_SmallCaption = 5,
+            eFont_StatusBar = 6,
+            eFont_Window = 7,
+            eFont_Document = 8,
+            eFont_Workspace = 9,
+            eFont_Desktop = 10,
+            eFont_Info = 11,
+            eFont_Dialog = 12,
+            eFont_Button = 13,
+            eFont_PullDownMenu = 14,
+            eFont_List = 15,
+            eFont_Field = 16,
+            eFont_Tooltips = 17,
+            eFont_Widget = 18,
+        }
+        #[test]
+        fn bindgen_test_layout_LookAndFeel() {
+            assert_eq!(::std::mem::size_of::<LookAndFeel>() , 1usize , concat
+                       ! ( "Size of: " , stringify ! ( LookAndFeel ) ));
+            assert_eq! (::std::mem::align_of::<LookAndFeel>() , 1usize ,
+                        concat ! (
+                        "Alignment of " , stringify ! ( LookAndFeel ) ));
+        }
+        impl Clone for LookAndFeel {
+            fn clone(&self) -> Self { *self }
+        }
+        #[repr(C)]
         #[derive(Debug)]
         pub struct PropertyStyleAnimationValuePair {
             pub mProperty: root::nsCSSPropertyID,
@@ -25509,6 +25791,32 @@ pub mod root {
     #[derive(Debug, Copy, Clone)]
     pub struct nsAttrValueOrString([u8; 0]);
     #[repr(C)]
+    #[derive(Debug, Copy)]
+    pub struct LookAndFeelInt {
+        pub id: i32,
+        pub value: i32,
+    }
+    #[test]
+    fn bindgen_test_layout_LookAndFeelInt() {
+        assert_eq!(::std::mem::size_of::<LookAndFeelInt>() , 8usize , concat !
+                   ( "Size of: " , stringify ! ( LookAndFeelInt ) ));
+        assert_eq! (::std::mem::align_of::<LookAndFeelInt>() , 4usize , concat
+                    ! ( "Alignment of " , stringify ! ( LookAndFeelInt ) ));
+        assert_eq! (unsafe {
+                    & ( * ( 0 as * const LookAndFeelInt ) ) . id as * const _
+                    as usize } , 0usize , concat ! (
+                    "Alignment of field: " , stringify ! ( LookAndFeelInt ) ,
+                    "::" , stringify ! ( id ) ));
+        assert_eq! (unsafe {
+                    & ( * ( 0 as * const LookAndFeelInt ) ) . value as * const
+                    _ as usize } , 4usize , concat ! (
+                    "Alignment of field: " , stringify ! ( LookAndFeelInt ) ,
+                    "::" , stringify ! ( value ) ));
+    }
+    impl Clone for LookAndFeelInt {
+        fn clone(&self) -> Self { *self }
+    }
+    #[repr(C)]
     #[derive(Debug, Copy, Clone)]
     pub struct RawServoAnimationValue([u8; 0]);
     #[repr(C)]
diff --git a/components/style/gecko_bindings/structs_release.rs b/components/style/gecko_bindings/structs_release.rs
index b723ba7c1ac..e7940b9824d 100644
--- a/components/style/gecko_bindings/structs_release.rs
+++ b/components/style/gecko_bindings/structs_release.rs
@@ -7295,6 +7295,288 @@ pub mod root {
         #[derive(Debug, Copy, Clone)]
         pub struct ContainerLayerParameters([u8; 0]);
         #[repr(C)]
+        #[derive(Debug, Copy)]
+        pub struct LookAndFeel {
+            pub _address: u8,
+        }
+        #[repr(u8)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_ColorID {
+            eColorID_WindowBackground = 0,
+            eColorID_WindowForeground = 1,
+            eColorID_WidgetBackground = 2,
+            eColorID_WidgetForeground = 3,
+            eColorID_WidgetSelectBackground = 4,
+            eColorID_WidgetSelectForeground = 5,
+            eColorID_Widget3DHighlight = 6,
+            eColorID_Widget3DShadow = 7,
+            eColorID_TextBackground = 8,
+            eColorID_TextForeground = 9,
+            eColorID_TextSelectBackground = 10,
+            eColorID_TextSelectForeground = 11,
+            eColorID_TextSelectForegroundCustom = 12,
+            eColorID_TextSelectBackgroundDisabled = 13,
+            eColorID_TextSelectBackgroundAttention = 14,
+            eColorID_TextHighlightBackground = 15,
+            eColorID_TextHighlightForeground = 16,
+            eColorID_IMERawInputBackground = 17,
+            eColorID_IMERawInputForeground = 18,
+            eColorID_IMERawInputUnderline = 19,
+            eColorID_IMESelectedRawTextBackground = 20,
+            eColorID_IMESelectedRawTextForeground = 21,
+            eColorID_IMESelectedRawTextUnderline = 22,
+            eColorID_IMEConvertedTextBackground = 23,
+            eColorID_IMEConvertedTextForeground = 24,
+            eColorID_IMEConvertedTextUnderline = 25,
+            eColorID_IMESelectedConvertedTextBackground = 26,
+            eColorID_IMESelectedConvertedTextForeground = 27,
+            eColorID_IMESelectedConvertedTextUnderline = 28,
+            eColorID_SpellCheckerUnderline = 29,
+            eColorID_activeborder = 30,
+            eColorID_activecaption = 31,
+            eColorID_appworkspace = 32,
+            eColorID_background = 33,
+            eColorID_buttonface = 34,
+            eColorID_buttonhighlight = 35,
+            eColorID_buttonshadow = 36,
+            eColorID_buttontext = 37,
+            eColorID_captiontext = 38,
+            eColorID_graytext = 39,
+            eColorID_highlight = 40,
+            eColorID_highlighttext = 41,
+            eColorID_inactiveborder = 42,
+            eColorID_inactivecaption = 43,
+            eColorID_inactivecaptiontext = 44,
+            eColorID_infobackground = 45,
+            eColorID_infotext = 46,
+            eColorID_menu = 47,
+            eColorID_menutext = 48,
+            eColorID_scrollbar = 49,
+            eColorID_threeddarkshadow = 50,
+            eColorID_threedface = 51,
+            eColorID_threedhighlight = 52,
+            eColorID_threedlightshadow = 53,
+            eColorID_threedshadow = 54,
+            eColorID_window = 55,
+            eColorID_windowframe = 56,
+            eColorID_windowtext = 57,
+            eColorID__moz_buttondefault = 58,
+            eColorID__moz_field = 59,
+            eColorID__moz_fieldtext = 60,
+            eColorID__moz_dialog = 61,
+            eColorID__moz_dialogtext = 62,
+            eColorID__moz_dragtargetzone = 63,
+            eColorID__moz_cellhighlight = 64,
+            eColorID__moz_cellhighlighttext = 65,
+            eColorID__moz_html_cellhighlight = 66,
+            eColorID__moz_html_cellhighlighttext = 67,
+            eColorID__moz_buttonhoverface = 68,
+            eColorID__moz_buttonhovertext = 69,
+            eColorID__moz_menuhover = 70,
+            eColorID__moz_menuhovertext = 71,
+            eColorID__moz_menubartext = 72,
+            eColorID__moz_menubarhovertext = 73,
+            eColorID__moz_eventreerow = 74,
+            eColorID__moz_oddtreerow = 75,
+            eColorID__moz_mac_buttonactivetext = 76,
+            eColorID__moz_mac_chrome_active = 77,
+            eColorID__moz_mac_chrome_inactive = 78,
+            eColorID__moz_mac_defaultbuttontext = 79,
+            eColorID__moz_mac_focusring = 80,
+            eColorID__moz_mac_menuselect = 81,
+            eColorID__moz_mac_menushadow = 82,
+            eColorID__moz_mac_menutextdisable = 83,
+            eColorID__moz_mac_menutextselect = 84,
+            eColorID__moz_mac_disabledtoolbartext = 85,
+            eColorID__moz_mac_secondaryhighlight = 86,
+            eColorID__moz_win_mediatext = 87,
+            eColorID__moz_win_communicationstext = 88,
+            eColorID__moz_nativehyperlinktext = 89,
+            eColorID__moz_comboboxtext = 90,
+            eColorID__moz_combobox = 91,
+            eColorID__moz_gtk_info_bar_text = 92,
+            eColorID_LAST_COLOR = 93,
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_IntID {
+            eIntID_CaretBlinkTime = 0,
+            eIntID_CaretWidth = 1,
+            eIntID_ShowCaretDuringSelection = 2,
+            eIntID_SelectTextfieldsOnKeyFocus = 3,
+            eIntID_SubmenuDelay = 4,
+            eIntID_MenusCanOverlapOSBar = 5,
+            eIntID_UseOverlayScrollbars = 6,
+            eIntID_AllowOverlayScrollbarsOverlap = 7,
+            eIntID_ShowHideScrollbars = 8,
+            eIntID_SkipNavigatingDisabledMenuItem = 9,
+            eIntID_DragThresholdX = 10,
+            eIntID_DragThresholdY = 11,
+            eIntID_UseAccessibilityTheme = 12,
+            eIntID_ScrollArrowStyle = 13,
+            eIntID_ScrollSliderStyle = 14,
+            eIntID_ScrollButtonLeftMouseButtonAction = 15,
+            eIntID_ScrollButtonMiddleMouseButtonAction = 16,
+            eIntID_ScrollButtonRightMouseButtonAction = 17,
+            eIntID_TreeOpenDelay = 18,
+            eIntID_TreeCloseDelay = 19,
+            eIntID_TreeLazyScrollDelay = 20,
+            eIntID_TreeScrollDelay = 21,
+            eIntID_TreeScrollLinesMax = 22,
+            eIntID_TabFocusModel = 23,
+            eIntID_ChosenMenuItemsShouldBlink = 24,
+            eIntID_WindowsDefaultTheme = 25,
+            eIntID_DWMCompositor = 26,
+            eIntID_WindowsClassic = 27,
+            eIntID_WindowsGlass = 28,
+            eIntID_TouchEnabled = 29,
+            eIntID_MacGraphiteTheme = 30,
+            eIntID_MacYosemiteTheme = 31,
+            eIntID_AlertNotificationOrigin = 32,
+            eIntID_ScrollToClick = 33,
+            eIntID_IMERawInputUnderlineStyle = 34,
+            eIntID_IMESelectedRawTextUnderlineStyle = 35,
+            eIntID_IMEConvertedTextUnderlineStyle = 36,
+            eIntID_IMESelectedConvertedTextUnderline = 37,
+            eIntID_SpellCheckerUnderlineStyle = 38,
+            eIntID_MenuBarDrag = 39,
+            eIntID_WindowsThemeIdentifier = 40,
+            eIntID_OperatingSystemVersionIdentifier = 41,
+            eIntID_ScrollbarButtonAutoRepeatBehavior = 42,
+            eIntID_TooltipDelay = 43,
+            eIntID_SwipeAnimationEnabled = 44,
+            eIntID_ColorPickerAvailable = 45,
+            eIntID_PhysicalHomeButton = 46,
+            eIntID_ScrollbarDisplayOnMouseMove = 47,
+            eIntID_ScrollbarFadeBeginDelay = 48,
+            eIntID_ScrollbarFadeDuration = 49,
+            eIntID_ContextMenuOffsetVertical = 50,
+            eIntID_ContextMenuOffsetHorizontal = 51,
+        }
+        #[repr(u32)]
+        /**
+   * Windows themes we currently detect.
+   */
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_WindowsTheme {
+            eWindowsTheme_Generic = 0,
+            eWindowsTheme_Classic = 1,
+            eWindowsTheme_Aero = 2,
+            eWindowsTheme_LunaBlue = 3,
+            eWindowsTheme_LunaOlive = 4,
+            eWindowsTheme_LunaSilver = 5,
+            eWindowsTheme_Royale = 6,
+            eWindowsTheme_Zune = 7,
+            eWindowsTheme_AeroLite = 8,
+        }
+        #[repr(u32)]
+        /**
+   * Operating system versions.
+   */
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_OperatingSystemVersion {
+            eOperatingSystemVersion_Windows7 = 2,
+            eOperatingSystemVersion_Windows8 = 3,
+            eOperatingSystemVersion_Windows10 = 4,
+            eOperatingSystemVersion_Unknown = 5,
+        }
+        pub const LookAndFeel_eScrollArrow_None:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_None;
+        pub const LookAndFeel_eScrollArrow_StartBackward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_StartBackward;
+        pub const LookAndFeel_eScrollArrow_StartForward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_StartForward;
+        pub const LookAndFeel_eScrollArrow_EndBackward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_EndBackward;
+        pub const LookAndFeel_eScrollArrow_EndForward:
+                  root::mozilla::LookAndFeel__bindgen_ty_1 =
+            LookAndFeel__bindgen_ty_1::eScrollArrow_EndForward;
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel__bindgen_ty_1 {
+            eScrollArrow_None = 0,
+            eScrollArrow_StartBackward = 4096,
+            eScrollArrow_StartForward = 256,
+            eScrollArrow_EndBackward = 16,
+            eScrollArrow_EndForward = 1,
+        }
+        pub const LookAndFeel_eScrollArrowStyle_Single:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_Single;
+        pub const LookAndFeel_eScrollArrowStyle_BothAtBottom:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_BothAtBottom;
+        pub const LookAndFeel_eScrollArrowStyle_BothAtEachEnd:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_BothAtEachEnd;
+        pub const LookAndFeel_eScrollArrowStyle_BothAtTop:
+                  root::mozilla::LookAndFeel__bindgen_ty_2 =
+            LookAndFeel__bindgen_ty_2::eScrollArrowStyle_BothAtTop;
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel__bindgen_ty_2 {
+            eScrollArrowStyle_Single = 4097,
+            eScrollArrowStyle_BothAtBottom = 17,
+            eScrollArrowStyle_BothAtEachEnd = 4369,
+            eScrollArrowStyle_BothAtTop = 4352,
+        }
+        pub const LookAndFeel_eScrollThumbStyle_Normal:
+                  root::mozilla::LookAndFeel__bindgen_ty_3 =
+            LookAndFeel__bindgen_ty_3::eScrollThumbStyle_Normal;
+        pub const LookAndFeel_eScrollThumbStyle_Proportional:
+                  root::mozilla::LookAndFeel__bindgen_ty_3 =
+            LookAndFeel__bindgen_ty_3::eScrollThumbStyle_Proportional;
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel__bindgen_ty_3 {
+            eScrollThumbStyle_Normal = 0,
+            eScrollThumbStyle_Proportional = 1,
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_FloatID {
+            eFloatID_IMEUnderlineRelativeSize = 0,
+            eFloatID_SpellCheckerUnderlineRelativeSize = 1,
+            eFloatID_CaretAspectRatio = 2,
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LookAndFeel_FontID {
+            eFont_Caption = 1,
+            eFont_Icon = 2,
+            eFont_Menu = 3,
+            eFont_MessageBox = 4,
+            eFont_SmallCaption = 5,
+            eFont_StatusBar = 6,
+            eFont_Window = 7,
+            eFont_Document = 8,
+            eFont_Workspace = 9,
+            eFont_Desktop = 10,
+            eFont_Info = 11,
+            eFont_Dialog = 12,
+            eFont_Button = 13,
+            eFont_PullDownMenu = 14,
+            eFont_List = 15,
+            eFont_Field = 16,
+            eFont_Tooltips = 17,
+            eFont_Widget = 18,
+        }
+        #[test]
+        fn bindgen_test_layout_LookAndFeel() {
+            assert_eq!(::std::mem::size_of::<LookAndFeel>() , 1usize , concat
+                       ! ( "Size of: " , stringify ! ( LookAndFeel ) ));
+            assert_eq! (::std::mem::align_of::<LookAndFeel>() , 1usize ,
+                        concat ! (
+                        "Alignment of " , stringify ! ( LookAndFeel ) ));
+        }
+        impl Clone for LookAndFeel {
+            fn clone(&self) -> Self { *self }
+        }
+        #[repr(C)]
         #[derive(Debug)]
         pub struct PropertyStyleAnimationValuePair {
             pub mProperty: root::nsCSSPropertyID,
@@ -24908,6 +25190,32 @@ pub mod root {
     #[derive(Debug, Copy, Clone)]
     pub struct nsAttrValueOrString([u8; 0]);
     #[repr(C)]
+    #[derive(Debug, Copy)]
+    pub struct LookAndFeelInt {
+        pub id: i32,
+        pub value: i32,
+    }
+    #[test]
+    fn bindgen_test_layout_LookAndFeelInt() {
+        assert_eq!(::std::mem::size_of::<LookAndFeelInt>() , 8usize , concat !
+                   ( "Size of: " , stringify ! ( LookAndFeelInt ) ));
+        assert_eq! (::std::mem::align_of::<LookAndFeelInt>() , 4usize , concat
+                    ! ( "Alignment of " , stringify ! ( LookAndFeelInt ) ));
+        assert_eq! (unsafe {
+                    & ( * ( 0 as * const LookAndFeelInt ) ) . id as * const _
+                    as usize } , 0usize , concat ! (
+                    "Alignment of field: " , stringify ! ( LookAndFeelInt ) ,
+                    "::" , stringify ! ( id ) ));
+        assert_eq! (unsafe {
+                    & ( * ( 0 as * const LookAndFeelInt ) ) . value as * const
+                    _ as usize } , 4usize , concat ! (
+                    "Alignment of field: " , stringify ! ( LookAndFeelInt ) ,
+                    "::" , stringify ! ( value ) ));
+    }
+    impl Clone for LookAndFeelInt {
+        fn clone(&self) -> Self { *self }
+    }
+    #[repr(C)]
     #[derive(Debug, Copy, Clone)]
     pub struct RawServoAnimationValue([u8; 0]);
     #[repr(C)]
diff --git a/components/style/properties/longhand/color.mako.rs b/components/style/properties/longhand/color.mako.rs
index 9fbdaac287a..436012bf461 100644
--- a/components/style/properties/longhand/color.mako.rs
+++ b/components/style/properties/longhand/color.mako.rs
@@ -6,6 +6,8 @@
 
 <% data.new_style_struct("Color", inherited=True) %>
 
+<% from data import to_rust_ident %>
+
 <%helpers:longhand name="color" need_clone="True" animatable="True"
                    spec="https://drafts.csswg.org/css-color/#color">
     use cssparser::RGBA;
@@ -53,4 +55,91 @@
     pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
         CSSColor::parse(context, input).map(SpecifiedValue)
     }
+
+    // FIXME(#15973): Add servo support for system colors
+    % if product == "gecko":
+        <%
+            # These are actually parsed. See nsCSSProps::kColorKTable
+            system_colors = """activeborder activecaption appworkspace background buttonface
+                               buttonhighlight buttonshadow buttontext captiontext graytext highlight
+                               highlighttext inactiveborder inactivecaption inactivecaptiontext
+                               infobackground infotext menu menutext scrollbar threeddarkshadow
+                               threedface threedhighlight threedlightshadow threedshadow window
+                               windowframe windowtext -moz-buttondefault -moz-buttonhoverface
+                               -moz-buttonhovertext -moz-cellhighlight -moz-cellhighlighttext
+                               -moz-eventreerow -moz-field -moz-fieldtext -moz-dialog -moz-dialogtext
+                               -moz-dragtargetzone -moz-gtk-info-bar-text -moz-html-cellhighlight
+                               -moz-html-cellhighlighttext -moz-mac-buttonactivetext
+                               -moz-mac-chrome-active -moz-mac-chrome-inactive
+                               -moz-mac-defaultbuttontext -moz-mac-focusring -moz-mac-menuselect
+                               -moz-mac-menushadow -moz-mac-menutextdisable -moz-mac-menutextselect
+                               -moz-mac-disabledtoolbartext -moz-mac-secondaryhighlight
+                               -moz-menuhover -moz-menuhovertext -moz-menubartext -moz-menubarhovertext
+                               -moz-oddtreerow -moz-win-mediatext -moz-win-communicationstext
+                               -moz-nativehyperlinktext -moz-comboboxtext -moz-combobox""".split()
+
+            # These are not parsed but must be serialized
+            # They are only ever set directly by Gecko
+            extra_colors = """WindowBackground WindowForeground WidgetBackground WidgetForeground
+                              WidgetSelectBackground WidgetSelectForeground Widget3DHighlight Widget3DShadow
+                              TextBackground TextForeground TextSelectBackground TextSelectForeground
+                              TextSelectForegroundCustom TextSelectBackgroundDisabled TextSelectBackgroundAttention
+                              TextHighlightBackground TextHighlightForeground IMERawInputBackground
+                              IMERawInputForeground IMERawInputUnderline IMESelectedRawTextBackground
+                              IMESelectedRawTextForeground IMESelectedRawTextUnderline
+                              IMEConvertedTextBackground IMEConvertedTextForeground IMEConvertedTextUnderline
+                              IMESelectedConvertedTextBackground IMESelectedConvertedTextForeground
+                              IMESelectedConvertedTextUnderline SpellCheckerUnderline""".split()
+        %>
+        use gecko_bindings::bindings::Gecko_GetLookAndFeelSystemColor;
+        use gecko_bindings::structs::root::mozilla::LookAndFeel_ColorID;
+        pub type SystemColor = LookAndFeel_ColorID;
+
+        impl ToCss for SystemColor {
+            fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+                let s = match *self {
+                    % for color in system_colors + extra_colors:
+                        LookAndFeel_ColorID::eColorID_${to_rust_ident(color)} => "${color}",
+                    % endfor
+                    LookAndFeel_ColorID::eColorID_LAST_COLOR => unreachable!(),
+                };
+                dest.write_str(s)
+            }
+        }
+
+        impl ToComputedValue for SystemColor {
+            type ComputedValue = u32; // nscolor
+            #[inline]
+            fn to_computed_value(&self, cx: &Context) -> Self::ComputedValue {
+                unsafe {
+                    Gecko_GetLookAndFeelSystemColor(*self as i32,
+                                                    &*cx.device.pres_context)
+                }
+            }
+
+            #[inline]
+            fn from_computed_value(_: &Self::ComputedValue) -> Self {
+                unreachable!()
+            }
+        }
+
+        impl SystemColor {
+            pub fn parse(input: &mut Parser) -> Result<Self, ()> {
+                use std::ascii::AsciiExt;
+                static PARSE_ARRAY: &'static [(&'static str, SystemColor); ${len(system_colors)}] = &[
+                    % for color in system_colors:
+                        ("${color}", LookAndFeel_ColorID::eColorID_${to_rust_ident(color)}),
+                    % endfor
+                ];
+
+                let ident = input.expect_ident()?;
+                for &(name, color) in PARSE_ARRAY.iter() {
+                    if name.eq_ignore_ascii_case(&ident) {
+                        return Ok(color)
+                    }
+                }
+                Err(())
+            }
+        }
+    % endif
 </%helpers:longhand>
diff --git a/components/style/values/computed/mod.rs b/components/style/values/computed/mod.rs
index 22f9e5e0996..f6e6ea2aa3b 100644
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@@ -132,6 +132,7 @@ impl ToComputedValue for specified::Color {
         let pres_context = unsafe { &*context.device.pres_context };
         match *self {
             specified::Color::RGBA(rgba) => rgba,
+            specified::Color::System(system) => to_rgba(system.to_computed_value(context)),
             specified::Color::CurrentColor => context.inherited_style.get_color().clone_color(),
             specified::Color::MozDefaultColor => to_rgba(pres_context.mDefaultColor),
             specified::Color::MozDefaultBackgroundColor => to_rgba(pres_context.mBackgroundColor),
diff --git a/components/style/values/specified/color.rs b/components/style/values/specified/color.rs
index 88063803d31..4a3c5498716 100644
--- a/components/style/values/specified/color.rs
+++ b/components/style/values/specified/color.rs
@@ -24,6 +24,7 @@ mod servo {
 mod gecko {
     use cssparser::{Color as CSSParserColor, Parser, RGBA};
     use parser::{Parse, ParserContext};
+    use properties::longhands::color::SystemColor;
     use std::fmt;
     use style_traits::ToCss;
     use values::HasViewportPercentage;
@@ -35,7 +36,8 @@ mod gecko {
         CurrentColor,
         /// A specific RGBA color
         RGBA(RGBA),
-
+        /// A system color
+        System(SystemColor),
         /// -moz-default-color
         MozDefaultColor,
         /// -moz-default-background-color
@@ -57,6 +59,8 @@ mod gecko {
                     CSSParserColor::CurrentColor => Ok(Color::CurrentColor),
                     CSSParserColor::RGBA(x) => Ok(Color::RGBA(x)),
                 }
+            } else if let Ok(system) = input.try(SystemColor::parse) {
+                Ok(Color::System(system))
             } else {
                 let ident = input.expect_ident()?;
                 match_ignore_ascii_case! { &ident,
@@ -77,6 +81,7 @@ mod gecko {
                 // Standard values:
                 Color::CurrentColor => CSSParserColor::CurrentColor.to_css(dest),
                 Color::RGBA(rgba) => rgba.to_css(dest),
+                Color::System(system) => system.to_css(dest),
 
                 // Non-standard values:
                 Color::MozDefaultColor => dest.write_str("-moz-default-color"),