fix: make window without rounded corners closable (#32612)

Co-authored-by: Cheng Zhao <zcbenz@gmail.com>

shell/browser/native_window_mac.mm

@@ -295,12 +295,12 @@ void ViewDidMoveToSuperview(NSView* self, SEL _cmd) {
 
   NSUInteger styleMask = NSWindowStyleMaskTitled;
 
-  // The NSWindowStyleMaskFullSizeContentView style removes rounded corners
-  // for framless window.
+  // Removing NSWindowStyleMaskTitled removes window title, which removes
+  // rounded corners of window.
   bool rounded_corner = true;
   options.Get(options::kRoundedCorners, &rounded_corner);
   if (!rounded_corner && !has_frame())
-    styleMask = NSWindowStyleMaskFullSizeContentView;
+    styleMask = 0;
 
   if (minimizable)
     styleMask |= NSMiniaturizableWindowMask;
@@ -1349,7 +1349,7 @@ void ViewDidMoveToSuperview(NSView* self, SEL _cmd) {
 
   if (vibrantView != nil && !vibrancy_type_.empty()) {
     const bool no_rounded_corner =
-        [window_ styleMask] & NSWindowStyleMaskFullSizeContentView;
+        !([window_ styleMask] & NSWindowStyleMaskTitled);
     if (!has_frame() && !is_modal() && !no_rounded_corner) {
       CGFloat radius;
       if (fullscreen) {

shell/browser/ui/cocoa/electron_ns_window.mm

@@ -159,6 +159,15 @@ - (NSView*)frameView {
   return [[self contentView] superview];
 }
 
+- (BOOL)validateUserInterfaceItem:(id<NSValidatedUserInterfaceItem>)item {
+  // By default "Close Window" is always disabled when window has no title, to
+  // support closing a window without title we need to manually do menu item
+  // validation. This code path is used by the "roundedCorners" option.
+  if ([item action] == @selector(performClose:))
+    return shell_->IsClosable();
+  return [super validateUserInterfaceItem:item];
+}
+
 // By overriding this built-in method the corners of the vibrant view (if set)
 // will be smooth.
 - (NSImage*)_cornerMask {
@@ -195,7 +204,10 @@ - (void)performClose:(id)sender {
   if (shell_->title_bar_style() ==
       electron::NativeWindowMac::TitleBarStyle::kCustomButtonsOnHover) {
     [[self delegate] windowShouldClose:self];
-  } else if (shell_->IsSimpleFullScreen()) {
+  } else if (!([self styleMask] & NSWindowStyleMaskTitled)) {
+    // performClose does not work for windows without title, so we have to
+    // emulate its behavior. This code path is used by "simpleFullscreen" and
+    // "roundedCorners" options.
     if ([[self delegate] respondsToSelector:@selector(windowShouldClose:)]) {
       if (![[self delegate] windowShouldClose:self])
         return;

spec-main/api-browser-window-spec.ts

@@ -110,6 +110,14 @@ describe('BrowserWindow module', () => {
       await closed;
     });
 
+    it('closes window without rounded corners', async () => {
+      await closeWindow(w);
+      w = new BrowserWindow({ show: false, frame: false, roundedCorners: false });
+      const closed = emittedOnce(w, 'closed');
+      w.close();
+      await closed;
+    });
+
     it('should not crash if called after webContents is destroyed', () => {
       w.webContents.destroy();
       w.webContents.on('destroyed', () => w.close());