wkwebview: move keyDown handler to WindowController so it doesn't require a click to activate

wkwebview/WebView/ViewController.swift

@@ -136,8 +136,4 @@ class ViewController: NSViewController, WKNavigationDelegate, WKUIDelegate, WKSc
 //        Implements window.close()
         self.view.window?.close();
     }
-
-    override func keyDown(with event: NSEvent) {
-//        Don't call super.keyDown so that it won't play the beeping noise.
-    }
 }

wkwebview/WebView/WindowController.swift

@@ -5,4 +5,8 @@ class WindowController : NSWindowController {
         super.init(coder: coder)
         shouldCascadeWindows = true
     }
+
+    override func keyDown(with event: NSEvent) {
+//        Don't call super.keyDown so that it won't play the beeping noise.
+    }
 }