Add simple fullscreen config

src/config-schema.js

@@ -637,6 +637,13 @@ if (process.platform === 'darwin') {
     description:
       'Experimental: A `custom` title bar adapts to theme colors. Choosing `custom-inset` adds a bit more padding. The title bar can also be completely `hidden`.<br>Note: Switching to a custom or hidden title bar will compromise some functionality.<br>This setting will require a relaunch of Atom to take effect.'
   };
+
+  configSchema.core.properties.simpleFullScreenWindows = {
+    type: 'boolean',
+    default: false,
+    description:
+      'Use pre-Lion fullscreen on macOS. This does not create a new desktop space for the atom on fullscreen mode.'
+  };
 }
 
 module.exports = configSchema;

src/main-process/atom-window.js

@@ -50,7 +50,8 @@ module.exports = class AtomWindow extends EventEmitter {
         disableBlinkFeatures: 'Auxclick',
         nodeIntegration: true,
         webviewTag: true
-      }
+      },
+      simpleFullscreen: this.getSimpleFullscreen()
     };
 
     // Don't set icon on Windows so the exe's ico will be used as window and
@@ -364,6 +365,10 @@ module.exports = class AtomWindow extends EventEmitter {
     return { x, y, width, height };
   }
 
+  getSimpleFullscreen() {
+    return this.atomApplication.config.get('core.simpleFullScreenWindows');
+  }
+
   shouldAddCustomTitleBar() {
     return (
       !this.isSpec &&