Remove platform conditionals from MediaQueryFeatures

https://bugs.webkit.org/show_bug.cgi?id=264870

Reviewed by Darin Adler.

Theme is included by all platforms and already defaults to false for
these methods if they are not implemented for a particular platform.

* Source/WebCore/css/query/MediaQueryFeatures.cpp:
(WebCore::MQ::Features::prefersContrast):
(WebCore::MQ::Features::prefersReducedMotion):

Canonical link: https://commits.webkit.org/270833@main

Source/WebCore/css/query/MediaQueryFeatures.cpp

@@ -515,11 +515,7 @@ const FeatureSchema& prefersContrast()
                 case ForcedAccessibilityValue::Off:
                     return false;
                 case ForcedAccessibilityValue::System:
-#if PLATFORM(MAC) || PLATFORM(IOS_FAMILY) || PLATFORM(GTK)
                     return Theme::singleton().userPrefersContrast();
-#else
-                    return false;
-#endif
                 }
                 return false;
             }();
@@ -559,11 +555,7 @@ const FeatureSchema& prefersReducedMotion()
                 case ForcedAccessibilityValue::Off:
                     return false;
                 case ForcedAccessibilityValue::System:
-#if USE(NEW_THEME) || PLATFORM(IOS_FAMILY)
                     return Theme::singleton().userPrefersReducedMotion();
-#else
-                    return false;
-#endif
                 }
                 return false;
             }();