Move guest view container message routing out of content/.

extensions/renderer/guest_view/extensions_guest_view_container_observer.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.
+
+#include "components/guest_view/renderer/guest_view_container_observer.h"
+
+namespace extensions {
+
+class ExtensionsGuestViewContainerObserver
+    : public guest_view::GuestViewContainerObserver {
+ public:
+  ExtensionsGuestViewContainerObserver();
+  ~ExtensionsGuestViewContainerObserver() override;
+
+ private:
+  // guest_view::GuestViewContainerObserver implementation.
+  bool HandlesMessage(const IPC::Message& message) override;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionsGuestViewContainerObserver);
+};
+
+}  // namespace extensions