Refactor GuestView construction

chrome/browser/guest_view/guest_view_base.h

 // Copyright 2014 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 CHROME_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 #define CHROME_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 
 #include <queue>
 
 #include "base/memory/weak_ptr.h"
@@ skipping 34 matching lines @@
 
   // Returns a *ViewGuest if this GuestView is of the given view type.
   template <typename T>
   T* As() {
     if (IsViewType(T::Type))
       return static_cast<T*>(this);
 
     return NULL;
   }
 
+  static void RegisterGuestViewTypes();
+
+  typedef base::Callback<GuestViewBase*(
+      content::BrowserContext*, int)> GuestCreationCallback;
+  static void RegisterGuestViewType(const std::string& view_type,
+                                    const GuestCreationCallback& callback);
+
   static GuestViewBase* Create(content::BrowserContext* browser_context,
                                int guest_instance_id,
                                const std::string& view_type);
 
   static GuestViewBase* FromWebContents(content::WebContents* web_contents);
 
   static GuestViewBase* From(int embedder_process_id, int instance_id);
 
   static bool IsGuest(content::WebContents* web_contents);
 
@@ skipping 206 matching lines @@
   scoped_ptr<EmbedderWebContentsObserver> embedder_web_contents_observer_;
 
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
   base::WeakPtrFactory<GuestViewBase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GuestViewBase);
 };
 
 #endif  // CHROME_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_