cocoa: add border cycling

Fixes #2430

video/out/cocoa/window.h

@@ -27,4 +27,5 @@
 - (BOOL)canBecomeKeyWindow;
 - (BOOL)canBecomeMainWindow;
 - (void)mulSize:(float)multiplier;
+- (void)updateBorder:(int)border;
 @end

video/out/cocoa/window.m

@@ -212,6 +212,34 @@
     [self.adapter putCommand:cmd];
 }
 
+- (void)updateBorder:(int)border
+{
+    int borderStyle = NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|
+                 NSWindowStyleMaskMiniaturizable;
+    if (border) {
+        int window_mask = [self styleMask] & ~NSWindowStyleMaskBorderless;
+        window_mask |= borderStyle;
+        [self setStyleMask:window_mask];
+    } else {
+        int window_mask = [self styleMask] & ~borderStyle;
+        window_mask |= NSWindowStyleMaskBorderless;
+        [self setStyleMask:window_mask];
+    }
+
+    if (![self.adapter isInFullScreenMode]) {
+        // XXX: workaround to force redrawing of window decoration
+        if (border) {
+            NSRect frame = [self frame];
+            frame.size.width += 1;
+            [self setFrame:frame display:YES];
+            frame.size.width -= 1;
+            [self setFrame:frame display:YES];
+        }
+
+        [self setContentAspectRatio:_unfs_content_frame.size];
+    }
+}
+
 - (NSRect)frameRect:(NSRect)f forCenteredContentSize:(NSSize)ns
 {
     NSRect cr  = [self contentRectForFrameRect:f];

video/out/cocoa_common.m

@@ -552,6 +552,20 @@ static int cocoa_set_window_title(struct vo *vo)
     return VO_TRUE;
 }
 
+static int vo_cocoa_window_border(struct vo *vo)
+{
+    struct vo_cocoa_state *s = vo->cocoa;
+    if (s->embedded)
+        return VO_NOTIMPL;
+
+    struct mp_vo_opts *opts = vo->opts;
+    [s->window updateBorder:opts->border];
+    if (opts->border)
+        cocoa_set_window_title(vo);
+
+    return VO_TRUE;
+}
+
 static void cocoa_screen_reconfiguration_observer(
     CGDirectDisplayID display, CGDisplayChangeSummaryFlags flags, void *ctx)
 {
@@ -747,6 +761,8 @@ static int vo_cocoa_control_on_main_thread(struct vo *vo, int request, void *arg
         return VO_TRUE;
     case VOCTRL_ONTOP:
         return vo_cocoa_ontop(vo);
+    case VOCTRL_BORDER:
+        return vo_cocoa_window_border(vo);
     case VOCTRL_GET_UNFS_WINDOW_SIZE: {
         int *sz = arg;
         NSSize size = [s->view frame].size;