RNTester: only show the Flatlist keyboard navigation switch on macOS

Author: Saadnajmi

packages/rn-tester/js/components/ListExampleShared.js

@@ -359,12 +359,18 @@ const styles = StyleSheet.create({
   },
   // [TODO(macOS GH#774)
   selectedItem: {
-    backgroundColor: PlatformColor('selectedContentBackgroundColor'),
+    backgroundColor: Platform.select({
+      macos: PlatformColor('selectedContentBackgroundColor'),
+      default: 'blue',
+    }),
   },
   selectedItemText: {
     // This was the closest UI Element color that looked right...
     // https://developer.apple.com/documentation/appkit/nscolor/ui_element_colors
-    color: PlatformColor('selectedMenuItemTextColor'),
+    color: Platform.select({
+      macos: PlatformColor('selectedMenuItemTextColor'),
+      default: 'white',
+    }),
   },
   // [TODO(macOS GH#774)]
 });

packages/rn-tester/js/examples/FlatList/FlatList-basic.js

@@ -185,11 +185,12 @@ class FlatListExample extends React.PureComponent<Props, State> {
                 this._setBooleanValue('useFlatListItemComponent'),
               )}
               {/* [TODO(macOS GH#774)  */}
-              {renderSmallSwitchOption(
-                'Keyboard Navigation',
-                this.state.enableSelectionOnKeyPress,
-                this._setBooleanValue('enableSelectionOnKeyPress'),
-              )}
+              {Platform.OS === 'macos' &&
+                renderSmallSwitchOption(
+                  'Keyboard Navigation',
+                  this.state.enableSelectionOnKeyPress,
+                  this._setBooleanValue('enableSelectionOnKeyPress'),
+                )}
               {/* TODO(macOS GH#774)] */}
               {Platform.OS === 'android' && (
                 <View>