Shortcuts: close tab keyboard shortcut

App/AppDelegate.swift

@@ -59,6 +59,13 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
                 action: #selector(ShortcutResponder.previousTab)
             ),
             
+            // Close tab
+            UIKeyCommand(
+                modifiers: [.command], input: "W",
+                title: "Close Tab",
+                action: #selector(ShortcutResponder.closeTab)
+            ),
+            
             // Next Tab
             UIKeyCommand(
                 modifiers: [.command, .shift], input: "]",

App/Browser View/BrowserViewController.swift

@@ -597,6 +597,20 @@ class BrowserViewController: UIViewController, WKNavigationDelegate, WKUIDelegat
         }
     }
     
+    func closeTab(_ sender: Any?) {
+        if tabController.tabs.count > 1 {
+            tabController.closeTab(self.tab)
+        } else {
+            #if targetEnvironment(macCatalyst)
+            if let originWindowScene = self.view.window?.windowScene {
+                UIApplication.shared.requestSceneSessionDestruction(originWindowScene.session, options: nil) { error in
+                    print("Error when requesting scene destruction: " + error.localizedDescription)
+                }
+            }
+            #endif
+        }
+    }
+    
     func findOnPage(_ sender: Any?) {
         browserView.setFindOnPageVisible(true, animated: true)
         findOnPageController.findOnPageView.textField.becomeFirstResponder()

App/KeyboardShortcuts.swift

@@ -27,6 +27,9 @@ protocol ShortcutResponder: class {
     @objc
     optional func nextTab(_ sender: Any?)
     
+    @objc
+    optional func closeTab(_ sender: Any?)
+    
     @objc
     optional func findOnPage(_ sender: Any?)
 }