Add disabled to accessibilityTraits in case button is disabled

Reviewed By: javache

Differential Revision: D4593622

fbshipit-source-id: 211f90f6af531a577af4e5487b43a3870f725bff

Libraries/Components/Button.js

@@ -111,11 +111,15 @@ class Button extends React.Component {
       'The title prop of a Button must be a string',
     );
     const formattedTitle = Platform.OS === 'android' ? title.toUpperCase() : title;
+    const accessibilityTraits = ['button'];
+    if (disabled) {
+      accessibilityTraits.push('disabled');
+    }
     return (
       <Touchable
         accessibilityComponentType="button"
         accessibilityLabel={accessibilityLabel}
-        accessibilityTraits={['button']}
+        accessibilityTraits={accessibilityTraits}
         testID={testID}
         disabled={disabled}
         onPress={onPress}>