REGRESSION: File attachment icons appear upside down

https://bugs.webkit.org/show_bug.cgi?id=248910
rdar://103089779

Reviewed by Simon Fraser.

Prior to WebKit#4954, attachment icons on macOS
were flipped in `IconMac` to preserve the correct orientation, however this
change removed that behavior in its refactoring.

This PR fixes this by adding back the flipping behavior where its needed
for attachemnts, which is in `RenderThemeMac::iconForAttachment`.

* Source/WebCore/rendering/RenderThemeMac.mm:
(WebCore::RenderThemeMac::iconForAttachment):

Canonical link: https://commits.webkit.org/257524@main

Author: rr-codes

Source/WebCore/rendering/RenderThemeMac.mm

@@ -2369,8 +2369,14 @@ static void TrackGradientInterpolate(void*, const CGFloat* inData, CGFloat* outD
     if (fileName.isNull() && attachmentType.isNull() && title.isNull())
         return nil;
 
-    if (auto icon = WebCore::iconForAttachment(fileName, attachmentType, title))
-        return adoptNS([[NSImage alloc] initWithCGImage:icon->image()->platformImage().get() size:NSZeroSize]);
+    if (auto icon = WebCore::iconForAttachment(fileName, attachmentType, title)) {
+        auto imageForIcon = adoptNS([[NSImage alloc] initWithCGImage:icon->image()->platformImage().get() size:NSZeroSize]);
+        // Need this because WebCore uses AppKit's flipped coordinate system exclusively.
+        ALLOW_DEPRECATED_DECLARATIONS_BEGIN
+        [imageForIcon setFlipped:YES];
+        ALLOW_DEPRECATED_DECLARATIONS_END
+        return imageForIcon;
+    }
 
     return nil;
 }