Make <webview> use out-of-process iframe architecture.

components/guest_view/renderer/iframe_guest_view_container.h

+// Copyright 2015 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 COMPONENTS_GUEST_VIEW_RENDERER_IFRAME_GUEST_VIEW_CONTAINER_H_
+#define COMPONENTS_GUEST_VIEW_RENDERER_IFRAME_GUEST_VIEW_CONTAINER_H_
+
+#include "components/guest_view/renderer/guest_view_container.h"
+
+namespace guest_view {
+
+// A GuestViewContainer whose container element is backed by an out-of-process
+// <iframe>.
+// This container handles messages related to guest attachment in
+// --site-per-process.
+class IframeGuestViewContainer : public GuestViewContainer {
+ public:
+  explicit IframeGuestViewContainer(content::RenderFrame* render_frame);
+  ~IframeGuestViewContainer() override;
+
+  // GuestViewContainer overrides.
+  bool OnMessage(const IPC::Message& message) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(IframeGuestViewContainer);
+};
+
+}  // namespace guest_view
+
+#endif  // COMPONENTS_GUEST_VIEW_RENDERER_IFRAME_GUEST_VIEW_CONTAINER_H_