Add support for Universal Links

Summary:
Adds support for [Universal Links](https://developer.apple.com/library/prerelease/ios/documentation/General/Conceptual/AppSearch/UniversalLinks.html).
Closes https://github.com/facebook/react-native/pull/4109

Reviewed By: svcscm

Differential Revision: D2658105

Pulled By: nicklockwood

fb-gh-sync-id: 7d94564f64cda7d31c79cf8f4c450ed2387057be

Libraries/LinkingIOS/LinkingIOS.js

@@ -43,9 +43,22 @@ var DEVICE_NOTIF_EVENT = 'openURL';
  * execution you'll need to add the following lines to you `*AppDelegate.m`:
  *
  * ```
- * - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation {
- *   return [RCTLinkingManager application:application openURL:url sourceApplication:sourceApplication annotation:annotation];
+ * - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url
+ *   sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
+ * {
+ *   return [RCTLinkingManager application:application openURL:url
+ *                       sourceApplication:sourceApplication annotation:annotation];
  * }
+ *
+ * // Only if your app is using [Universal Links](https://developer.apple.com/library/prerelease/ios/documentation/General/Conceptual/AppSearch/UniversalLinks.html).
+ * - (BOOL)application:(UIApplication *)application continueUserActivity:(NSUserActivity *)userActivity
+ *  restorationHandler:(void (^)(NSArray * _Nullable))restorationHandler
+ * {
+ *  return [RCTLinkingManager application:application
+ *                   continueUserActivity:userActivity
+ *                     restorationHandler:restorationHandler];
+ * }
+ *
  * ```
  *
  * And then on your React component you'll be able to listen to the events on
@@ -71,7 +84,7 @@ var DEVICE_NOTIF_EVENT = 'openURL';
  * LinkingIOS.openURL(url)
  * ```
  *
- * If you want to check if any installed app can handle a given URL beforehand you can call
+ * If you want to check if any installed app can handle a given URL beforehand, call
  * ```
  * LinkingIOS.canOpenURL(url, (supported) => {
  *   if (!supported) {
@@ -130,7 +143,7 @@ class LinkingIOS {
    * Determine whether or not an installed app can handle a given URL.
    * The callback function will be called with `bool supported` as the only argument
    *
-   * NOTE: As of iOS 9, your app needs to provide a `LSApplicationQueriesSchemes` key
+   * NOTE: As of iOS 9, your app needs to provide the `LSApplicationQueriesSchemes` key
    * inside `Info.plist`.
    */
   static canOpenURL(url: string, callback: Function) {

Libraries/LinkingIOS/RCTLinkingManager.h

@@ -18,4 +18,8 @@
   sourceApplication:(NSString *)sourceApplication
          annotation:(id)annotation;
 
++ (BOOL)application:(UIApplication *)application
+continueUserActivity:(NSUserActivity *)userActivity
+  restorationHandler:(void (^)(NSArray *))restorationHandler;
+
 @end

Libraries/LinkingIOS/RCTLinkingManager.m

@@ -54,6 +54,19 @@ RCT_EXPORT_MODULE()
   return YES;
 }
 
++ (BOOL)application:(UIApplication *)application
+continueUserActivity:(NSUserActivity *)userActivity
+  restorationHandler:(void (^)(NSArray *))restorationHandler
+{
+  if ([userActivity.activityType isEqualToString:NSUserActivityTypeBrowsingWeb]) {
+    NSDictionary *payload = @{@"url": userActivity.webpageURL.absoluteString};
+    [[NSNotificationCenter defaultCenter] postNotificationName:RCTOpenURLNotification
+                                                        object:self
+                                                      userInfo:payload];
+  }
+  return YES;
+}
+
 - (void)handleOpenURLNotification:(NSNotification *)notification
 {
   [_bridge.eventDispatcher sendDeviceEventWithName:@"openURL"
@@ -62,6 +75,7 @@ RCT_EXPORT_MODULE()
 
 RCT_EXPORT_METHOD(openURL:(NSURL *)URL)
 {
+  // TODO: we should really return success/failure via a callback here
   // Doesn't really matter what thread we call this on since it exits the app
   [RCTSharedApplication() openURL:URL];
 }
@@ -72,7 +86,8 @@ RCT_EXPORT_METHOD(canOpenURL:(NSURL *)URL
   if (RCTRunningInAppExtension()) {
     // Technically Today widgets can open urls, but supporting that would require
     // a reference to the NSExtensionContext
-    callback(@[@(NO)]);
+    callback(@[@NO]);
+    return;
   }
 
   // This can be expensive, so we deliberately don't call on main thread