Upstream JavaScript injection for iOS

ios/web/web_view_util.mm

Index: ios/web/web_view_util.mm
diff --git a/ios/web/web_view_util.mm b/ios/web/web_view_util.mm
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+// Copyright 2014 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/web/web_view_util.h"
+
+#include "base/ios/ios_util.h"
+
+namespace {
+
+// If true, UIWebView is always used even if WKWebView is available.
+bool g_force_ui_web_view = false;
+
+}  // namespace
+
+namespace web {
+
+bool IsWKWebViewEnabled() {
+#if defined(ENABLE_WKWEBVIEW)
+  // Eventually this may be a dynamic flag, but for now it's purely a
+  // compile-time option.
+  return !g_force_ui_web_view && base::ios::IsRunningOnIOS8OrLater();
+#else
+  return false;
+#endif
+}
+
+void SetForceUIWebView(bool flag) {
+  g_force_ui_web_view = flag;
+}
+
+bool GetForceUIWebView() {
+  return g_force_ui_web_view;
+}
+
+}  // namespace web