(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 221 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,

[Mike West, 2016/09/14 09:21:24]

We have a host at this point, whereas we don't have a response during
`CANCELING_REQUEST`.

     READY_TO_COMMIT,
     DID_COMMIT,
     DID_COMMIT_ERROR_PAGE,
   };
 
   NavigationHandleImpl(const GURL& url,
                        FrameTreeNode* frame_tree_node,
                        bool is_renderer_initiated,
                        bool is_synchronous,
                        bool is_srcdoc,
@@ skipping 69 matching lines @@
   std::unique_ptr<NavigationData> navigation_data_;
 
   SSLStatus ssl_status_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationHandleImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_