[content shell] change how the main render view is picked for layout tests

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 {
 
+class RenderView;
+
 // 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);
+void EnableWebTestProxyCreation(const base::Callback<
+    void(RenderView*, WebTestRunner::WebTestProxyBase*)>& callback);
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_