feat(NativeWindowMac): addTabbedWindow

Add support for the [`NSWindow addTabbedWindow`][nsw] method on MacOSX

This plays nicely with the changes from #9052 and #9725

Usage samples available in [this commit][c] in my fork of
`electron-quick-start`

[nsw]: 1855947-addtabbedwindow
[c]: 79f06591df

atom/browser/native_window_mac.mm

@@ -474,6 +474,7 @@ enum {
 @interface NSWindow (SierraSDK)
 - (void)setTabbingMode:(NSInteger)mode;
 - (void)setTabbingIdentifier:(NSString*)identifier;
+- (void)addTabbedWindow:(NSWindow*)window ordered:(NSWindowOrderingMode)ordered;
 - (IBAction)selectPreviousTab:(id)sender;
 - (IBAction)selectNextTab:(id)sender;
 - (IBAction)mergeAllWindows:(id)sender;
@@ -1649,6 +1650,12 @@ void NativeWindowMac::ToggleTabBar() {
   }
 }
 
+void NativeWindowMac::AddTabbedWindow(NativeWindow* window) {
+  if ([window_ respondsToSelector:@selector(addTabbedWindow:ordered:)]) {
+    [window_ addTabbedWindow:window->GetNativeWindow() ordered:NSWindowAbove];
+  }
+}
+
 void NativeWindowMac::SetVibrancy(const std::string& type) {
   if (!base::mac::IsAtLeastOS10_10()) return;