Add platform_view_swift based on platform_view example (#10)

platform_view_swift/ios/Runner/PlatformViewController.swift

@@ -0,0 +1,37 @@
+// Copyright 2018, the Flutter project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import UIKit
+import Foundation
+
+protocol PlatformViewControllerDelegate {
+  func didUpdateCounter(counter: Int)
+}
+
+class PlatformViewController : UIViewController {
+  var delegate: PlatformViewControllerDelegate? = nil
+  var counter: Int = 0
+
+  @IBOutlet weak var incrementLabel: UILabel!
+
+  override func viewDidLoad() {
+    super.viewDidLoad()
+    setIncrementLabelText()
+  }
+
+  func handleIncrement(_ sender: Any) {
+    self.counter += 1
+    self.setIncrementLabelText()
+  }
+
+  func switchToFlutterView(_ sender: Any) {
+    self.delegate?.didUpdateCounter(counter: self.counter)
+    dismiss(animated:false, completion:nil)
+  }
+
+  func setIncrementLabelText() {
+    let text = String(format: "Button tapped %d %@", self.counter, (self.counter == 1) ? "time" : "times")
+    self.incrementLabel.text = text;
+  }
+}