Create a new RenderFrameHost per child frame when --site-per-process is enabled.

content/browser/renderer_host/render_frame_message_filter.h

Index: content/browser/renderer_host/render_frame_message_filter.h
diff --git a/content/browser/renderer_host/render_frame_message_filter.h b/content/browser/renderer_host/render_frame_message_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..73369b0be3319d3177ec89147eb77228b3704f1d
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+++ b/content/browser/renderer_host/render_frame_message_filter.h
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+// Copyright (c) 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_BROWSER_RENDERER_HOST_RENDER_FRAME_MESSAGE_FILTER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_RENDER_FRAME_MESSAGE_FILTER_H_
+
+#include "content/public/browser/browser_message_filter.h"
+
+namespace content {
+class RenderWidgetHelper;
+
+// RenderFrameMessageFilter intercepts FrameHost messages on the IO thread
+// that require low-latency processing. The canoncial example of this is
+// child-frame creation which is a sync IPC that provides the renderer
+// with the routing id for a newly created RenderFrame.
+//
+// This object is created on the UI thread and used on the IO thread.
+class RenderFrameMessageFilter : public BrowserMessageFilter {
+ public:
+  RenderFrameMessageFilter(int render_process_id,
+                           RenderWidgetHelper* render_widget_helper);
+
+  virtual bool OnMessageReceived(const IPC::Message& message,
+                                 bool* message_was_ok) OVERRIDE;
+
+ private:
+  virtual ~RenderFrameMessageFilter();
+
+  void OnCreateChildFrame(int parent_render_frame_id,
+                          int64 parent_frame_id,
+                          int64 frame_id,
+                          const std::string& frame_name,
+                          int* new_render_frame_id);
+
+  const int render_process_id_;
+
+  // Needed for issuing routing ids and surface ids.
+  scoped_refptr<RenderWidgetHelper> render_widget_helper_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_FRAME_MESSAGE_FILTER_H_