feat: add nativeTheme.shouldDifferentiateWithoutColor on macOS

Adds nativeTheme.shouldDifferentiateWithoutColor on macOS that maps to
NSWorkspace.accessibilityDisplayShouldDifferentiateWithoutColor. If true,
the user has indicated that they prefer UI that differentiates items with
something other than color alone. This is useful for users with color
vision deficiency.

docs/api/native-theme.md

@@ -84,3 +84,7 @@ Currently, Windows high contrast is the only system setting that triggers forced
 ### `nativeTheme.prefersReducedTransparency` _Readonly_
 
 A `boolean` that indicates whether the user has chosen via system accessibility settings to reduce transparency at the OS level.
+
+### `nativeTheme.shouldDifferentiateWithoutColor` _macOS_ _Readonly_
+
+A `boolean` that indicates whether the user prefers UI that differentiates items using something other than color alone (e.g. shapes or labels). This maps to [NSWorkspace.accessibilityDisplayShouldDifferentiateWithoutColor](https://developer.apple.com/documentation/appkit/nsworkspace/accessibilitydisplayshoulddifferentiatewithoutcolor).

shell/browser/api/electron_api_native_theme.cc

@@ -147,7 +147,12 @@ gin::ObjectTemplateBuilder NativeTheme::GetObjectTemplateBuilder(
                    &NativeTheme::ShouldUseInvertedColorScheme)
       .SetProperty("inForcedColorsMode", &NativeTheme::InForcedColorsMode)
       .SetProperty("prefersReducedTransparency",
-                   &NativeTheme::GetPrefersReducedTransparency);
+                   &NativeTheme::GetPrefersReducedTransparency)
+#if BUILDFLAG(IS_MAC)
+      .SetProperty("shouldDifferentiateWithoutColor",
+                   &NativeTheme::ShouldDifferentiateWithoutColor)
+#endif
+      ;
 }
 
 const char* NativeTheme::GetTypeName() {

shell/browser/api/electron_api_native_theme.h

@@ -56,6 +56,9 @@ class NativeTheme final : public gin_helper::DeprecatedWrappable<NativeTheme>,
   bool ShouldUseInvertedColorScheme();
   bool InForcedColorsMode();
   bool GetPrefersReducedTransparency();
+#if BUILDFLAG(IS_MAC)
+  bool ShouldDifferentiateWithoutColor();
+#endif
 
   // ui::NativeThemeObserver:
   void OnNativeThemeUpdated(ui::NativeTheme* theme) override;

shell/browser/api/electron_api_native_theme_mac.mm

@@ -26,4 +26,9 @@ void NativeTheme::UpdateMacOSAppearanceForOverrideValue(
   [[NSApplication sharedApplication] setAppearance:new_appearance];
 }
 
+bool NativeTheme::ShouldDifferentiateWithoutColor() {
+  return [[NSWorkspace sharedWorkspace]
+      accessibilityDisplayShouldDifferentiateWithoutColor];
+}
+
 }  // namespace electron::api

spec/api-native-theme-spec.ts

@@ -6,6 +6,7 @@ import { once } from 'node:events';
 import * as path from 'node:path';
 import { setTimeout } from 'node:timers/promises';
 
+import { ifdescribe } from './lib/spec-helpers';
 import { closeAllWindows } from './lib/window-helpers';
 
 describe('nativeTheme module', () => {
@@ -119,4 +120,10 @@ describe('nativeTheme module', () => {
       expect(nativeTheme.prefersReducedTransparency).to.be.a('boolean');
     });
   });
+
+  ifdescribe(process.platform === 'darwin')('nativeTheme.shouldDifferentiateWithoutColor', () => {
+    it('returns a boolean', () => {
+      expect(nativeTheme.shouldDifferentiateWithoutColor).to.be.a('boolean');
+    });
+  });
 });