Introduce AncestorThrottle, which will process 'X-Frame-Options' headers.

content/content_browser.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base_static',
     '../cc/cc.gyp:cc',
     '../cc/cc.gyp:cc_surfaces',
     '../components/components.gyp:display_compositor',
@@ skipping 723 matching lines @@
       'browser/fileapi/browser_file_system_helper.h',
       'browser/fileapi/chrome_blob_storage_context.cc',
       'browser/fileapi/chrome_blob_storage_context.h',
       'browser/fileapi/fileapi_message_filter.cc',
       'browser/fileapi/fileapi_message_filter.h',
       'browser/fileapi/upload_file_system_file_element_reader.cc',
       'browser/fileapi/upload_file_system_file_element_reader.h',
       'browser/find_request_manager.cc',
       'browser/find_request_manager.h',
       'browser/font_list_async.cc',
+      'browser/frame_host/ancestor_throttle.cc',
+      'browser/frame_host/ancestor_throttle.h',
       'browser/frame_host/cross_process_frame_connector.cc',
       'browser/frame_host/cross_process_frame_connector.h',
       'browser/frame_host/cross_site_transferring_request.cc',
       'browser/frame_host/cross_site_transferring_request.h',
       'browser/frame_host/debug_urls.cc',
       'browser/frame_host/debug_urls.h',
       'browser/frame_host/frame_mojo_shell.cc',
       'browser/frame_host/frame_mojo_shell.h',
       'browser/frame_host/frame_navigation_entry.cc',
       'browser/frame_host/frame_navigation_entry.h',
@@ skipping 1457 matching lines @@
       ],
     }],
     ['OS != "mac" and OS != "android"', {
       'sources!': [
         'browser/gpu/gpu_surface_tracker.cc',
         'browser/gpu/gpu_surface_tracker.h',
       ],
     }],
   ],
 }