[iOS] Upstream switches and flags controlling which WebView is used

ios/chrome/browser/web/web_view_type_util.mm

Index: ios/chrome/browser/web/web_view_type_util.mm
diff --git a/ios/chrome/browser/web/web_view_type_util.mm b/ios/chrome/browser/web/web_view_type_util.mm
new file mode 100644
index 0000000000000000000000000000000000000000..e27d23fc475e39797cbb7179c68b2b1eb14b1ccd
--- /dev/null
+++ b/ios/chrome/browser/web/web_view_type_util.mm
@@ -0,0 +1,16 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ios/chrome/browser/web/web_view_type_util.h"
+
+#include "ios/chrome/browser/experimental_flags.h"
+
+namespace web_view_type_util {
+
+web::WebViewType GetWebViewType() {
+  return experimental_flags::IsWKWebViewEnabled() ? web::WK_WEB_VIEW_TYPE
+                                                  : web::UI_WEB_VIEW_TYPE;
+}
+
+}  // namespace web_view_type_util