Fix OIDExternalUserAgentIOSCustomBrowser on iOS 10+ (#871)

Author: loic-sharma

Sources/AppAuth/iOS/OIDExternalUserAgentIOSCustomBrowser.m

@@ -145,16 +145,26 @@ - (BOOL)presentExternalUserAgentRequest:(nonnull id<OIDExternalUserAgentRequest>
     NSString *testURLString = [NSString stringWithFormat:@"%@://example.com", _canOpenURLScheme];
     NSURL *testURL = [NSURL URLWithString:testURLString];
     if (![[UIApplication sharedApplication] canOpenURL:testURL]) {
-      [[UIApplication sharedApplication] openURL:_appStoreURL];
+      if (@available(iOS 10.0, *)) {
+        [[UIApplication sharedApplication] openURL:_appStoreURL options:@{} completionHandler:nil];
+      } else {
+        [[UIApplication sharedApplication] openURL:_appStoreURL];
+      }
       return NO;
     }
   }
 
   // Transforms the request URL and opens it.
   NSURL *requestURL = [request externalUserAgentRequestURL];
   requestURL = _URLTransformation(requestURL);
-  BOOL openedInBrowser = [[UIApplication sharedApplication] openURL:requestURL];
-  return openedInBrowser;
+  if (@available(iOS 10.0, *)) {
+    BOOL willOpen = [[UIApplication sharedApplication] canOpenURL:requestURL];
+    [[UIApplication sharedApplication] openURL:requestURL options:@{} completionHandler:nil];
+    return willOpen;
+  } else {
+    BOOL openedInBrowser = [[UIApplication sharedApplication] openURL:requestURL];
+    return openedInBrowser;
+  }
 }
 
 - (void)dismissExternalUserAgentAnimated:(BOOL)animated