Use the WebTestProxy for layout tests in content_shell

content/public/test/layouttest_support.h

+// Copyright (c) 2012 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.
+
+#ifndef CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_
+#define CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_
+
+#include "base/callback_forward.h"
+
+namespace WebTestRunner {
+class WebTestProxyBase;
+}
+
+namespace content {
+
+// Enable injecting of a WebTestProxy between WebViews and RenderViews.
+// |callback| is invoked with a pointer to WebTestProxyBase for each created
+// WebTestProxy.
+void EnableWebTestProxyCreation(
+    const base::Callback<void(WebTestRunner::WebTestProxyBase*)>& callback);
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_