[LayoutSpecExamples] Added swift counterpart. (#2576)

* [LayoutSpecExamples] Added swift counterpart.

* Fixed copyright text.

examples/LayoutSpecExamples-Swift/Sample/OverviewViewController.swift

@@ -0,0 +1,70 @@
+//
+//  OverviewViewController.swift
+//  Sample
+//
+//  Copyright (c) 2014-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+//  FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+//  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+//  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+import AsyncDisplayKit
+
+class OverviewViewController: ASViewController<ASTableNode> {
+  let tableNode = ASTableNode()
+  let layoutExamples: [LayoutExampleNode.Type]
+
+  init() {
+    layoutExamples = [
+      HeaderWithRightAndLeftItems.self,
+      PhotoWithInsetTextOverlay.self,
+      PhotoWithOutsetIconOverlay.self,
+      FlexibleSeparatorSurroundingContent.self
+    ]
+
+    super.init(node: tableNode)
+
+    self.title = "Layout Examples"
+    self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
+    tableNode.delegate = self
+    tableNode.dataSource = self
+  }
+  
+  required init?(coder aDecoder: NSCoder) {
+    fatalError("init(coder:) has not been implemented")
+  }
+
+  override func viewWillAppear(_ animated: Bool) {
+    super.viewWillAppear(animated)
+
+    if let indexPath = tableNode.indexPathForSelectedRow {
+      tableNode.deselectRow(at: indexPath, animated: true)
+    }
+  }
+
+}
+
+extension OverviewViewController: ASTableDataSource {
+  func tableNode(_ tableNode: ASTableNode, numberOfRowsInSection section: Int) -> Int {
+    return layoutExamples.count
+  }
+
+  func tableNode(_ tableNode: ASTableNode, nodeForRowAt indexPath: IndexPath) -> ASCellNode {
+    return OverviewCellNode(layoutExampleType: layoutExamples[indexPath.row])
+  }
+}
+
+extension OverviewViewController: ASTableDelegate {
+  func tableNode(_ tableNode: ASTableNode, didSelectRowAt indexPath: IndexPath) {
+    let layoutExampleType = (tableNode.nodeForRow(at: indexPath) as! OverviewCellNode).layoutExampleType
+    let detail = LayoutExampleViewController(layoutExampleType: layoutExampleType)
+    self.navigationController?.pushViewController(detail, animated: true)
+  }
+}