feat: Add BrowserWindow.setWindowButtonVisibility()

Fixes #12701 and supersedes #13131.

Ideally we would have added `setTitleBarStyle()`, but that is a
significantly more involved change. For example, consider the case where
we switch from `hidden` to `normal`. We would not only have to show the
traffic light buttons, we would also have to switch the window from a
frameless to a framed window and deal with various other window state.
Lets instead implement a simple solution for #12701.

atom/browser/api/atom_api_top_level_window.cc

@@ -738,6 +738,13 @@ void TopLevelWindow::AddTabbedWindow(NativeWindow* window,
     args->ThrowError("AddTabbedWindow cannot be called by a window on itself.");
 }
 
+void TopLevelWindow::SetWindowButtonVisibility(bool visible,
+                                               mate::Arguments* args) {
+  if (!window_->SetWindowButtonVisibility(visible)) {
+    args->ThrowError("Not supported for this window");
+  }
+}
+
 void TopLevelWindow::SetAutoHideMenuBar(bool auto_hide) {
   window_->SetAutoHideMenuBar(auto_hide);
 }
@@ -1030,6 +1037,8 @@ void TopLevelWindow::BuildPrototype(v8::Isolate* isolate,
       .SetMethod("moveTabToNewWindow", &TopLevelWindow::MoveTabToNewWindow)
       .SetMethod("toggleTabBar", &TopLevelWindow::ToggleTabBar)
       .SetMethod("addTabbedWindow", &TopLevelWindow::AddTabbedWindow)
+      .SetMethod("setWindowButtonVisibility",
+                 &TopLevelWindow::SetWindowButtonVisibility)
 #endif
       .SetMethod("setAutoHideMenuBar", &TopLevelWindow::SetAutoHideMenuBar)
       .SetMethod("isMenuBarAutoHide", &TopLevelWindow::IsMenuBarAutoHide)

atom/browser/api/atom_api_top_level_window.h

@@ -173,6 +173,7 @@ class TopLevelWindow : public mate::TrackableObject<TopLevelWindow>,
   void MoveTabToNewWindow();
   void ToggleTabBar();
   void AddTabbedWindow(NativeWindow* window, mate::Arguments* args);
+  void SetWindowButtonVisibility(bool visible, mate::Arguments* args);
   void SetAutoHideMenuBar(bool auto_hide);
   bool IsMenuBarAutoHide();
   void SetMenuBarVisibility(bool visible);