Explicitly initialize secondary renderers for layout tests.

content/shell/renderer/layout_test/layout_test_render_frame_observer.h

 // Copyright 2013 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_SHELL_RENDERER_LAYOUT_TEST_LAYOUT_TEST_RENDER_FRAME_OBSERVER_H_
 #define CONTENT_SHELL_RENDERER_LAYOUT_TEST_LAYOUT_TEST_RENDER_FRAME_OBSERVER_H_
 
 #include "base/macros.h"
 #include "content/public/renderer/render_frame_observer.h"
 
@@ skipping 19 matching lines @@
 
  private:
   void OnLayoutDumpRequest();
   void OnReplicateLayoutTestRuntimeFlagsChanges(
       const base::DictionaryValue& changed_layout_test_runtime_flags);
   void OnSetTestConfiguration(const ShellTestConfiguration& test_config);
   void OnReplicateTestConfiguration(
       const ShellTestConfiguration& test_config,
       const base::DictionaryValue&
           accumulated_layout_test_runtime_flags_changes);
+  void OnSetupSecondaryRenderer();
 
   DISALLOW_COPY_AND_ASSIGN(LayoutTestRenderFrameObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_RENDERER_LAYOUT_TEST_LAYOUT_TEST_RENDER_FRAME_OBSERVER_H_