(Re-)introduce AncestorThrottle to handle 'X-Frame-Options'.

content/browser/frame_host/navigation_handle_impl.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 CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_
 
 #include "content/public/browser/navigation_handle.h"
 
 #include <stddef.h>
@@ skipping 275 matching lines @@
  private:
   friend class NavigationHandleImplTest;
 
   // Used to track the state the navigation is currently in.
   enum State {
     INITIAL = 0,
     WILL_SEND_REQUEST,
     DEFERRING_START,
     WILL_REDIRECT_REQUEST,
     DEFERRING_REDIRECT,
-    CANCELING,
+    CANCELING_REQUEST,
     WILL_PROCESS_RESPONSE,
     DEFERRING_RESPONSE,
+    CANCELING_RESPONSE,

[clamy, 2016/12/06 17:09:43]

What is the difference between CANCELING_REQUEST & CANCELING_RESPONSE?

[arthursonzogni, 2016/12/07 16:25:02]

According to me,
* CANCELLING_REQUEST happens when the request is cancelled and no network
request has been made.
* CANCELLING_RESPONSE happens when the network request has been made and the
response has be received. The navigation is canceled at this point.

Why can't we only have one common state? I don't know, I think it could be
useful for test only.
I will merge the two for the moment. @mkwst do you objections?

     READY_TO_COMMIT,
     DID_COMMIT,
     DID_COMMIT_ERROR_PAGE,
   };
 
   NavigationHandleImpl(const GURL& url,
                        FrameTreeNode* frame_tree_node,
                        bool is_renderer_initiated,
                        bool is_same_page,
                        bool is_srcdoc,
@@ skipping 122 matching lines @@
   std::string searchable_form_encoding_;
 
   base::WeakPtrFactory<NavigationHandleImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationHandleImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_