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

content/renderer/render_frame_impl.cc

 // Copyright 2013 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 "content/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 2322 matching lines @@
   std::string error_html;
   GetContentClient()->renderer()->GetNavigationErrorStrings(
       this, failed_request, error, &error_html, nullptr);
 
   blink::WebFrameLoadType frame_load_type =
       entry ? blink::WebFrameLoadType::BackForward
             : blink::WebFrameLoadType::Standard;
   const blink::WebHistoryItem& history_item =
       entry ? entry->root() : blink::WebHistoryItem();
 
+  // Requests blocked by the X-Frame-Options or by the CSP directive
+  // frame-ancestor don't display error pages but blank pages instead.

[alexmos, 2016/11/30 01:22:19]

I think this CL only moves XFO to the browser process, but not CSP
frame-ancestors, so let's not mention frame-ancestors here until we move it over
as well :)

[arthursonzogni, 2016/11/30 13:49:55]

Done.

+  // See crbug.com/622385 if you want to remove this.

[alexmos, 2016/11/30 01:22:19]

Let's rephrase this as a TODO to remove this once error pages commit in the
right process.  Feel free to include myself, mkwst, and/or yourself as the
TODO() target. :)  Let's also reference crbug.com/588314 in addition to 622385.

[arthursonzogni, 2016/11/30 13:49:55]

Done.

+  if (error.reason == net::ERR_BLOCKED_BY_RESPONSE) {
+    frame_->loadData("", WebString::fromUTF8("text/html"),
+                     WebString::fromUTF8("UTF-8"),
+                     GURL("data:text/html,"), WebURL(), replace,

[alexmos, 2016/11/30 01:22:19]

Existing code uses SecurityOrigin::urlWithUniqueSecurityOrigin(), which is
defined as "data:,".  Perhaps we can reuse that URL here?

[arthursonzogni, 2016/11/30 13:49:55]

Done.

+                     frame_load_type, history_item,
+                     blink::WebHistoryDifferentDocumentLoad, false);
+    return;
+  }

[arthursonzogni, 2016/11/23 17:38:51]

Some justifications about this:
* I use "" to load a blank page.
* I use GURL("data:text/html,") such that forward/backward navigation reloads a
blank page and not something else. GURL("about:blank") is not a better
alternative because in that case, the parent frame is allowed to access its
children, which is forbidden.

The behavior is the same as the actual one. Once there is no more problems with
error pages, this block should be removed.

[alexmos, 2016/11/30 01:22:19]

Ack.  This seems fairly similar to what is currently done by
DocumentLoader::cancelLoadAfterXFrameOptionsOrCSPDenied.

+
   frame_->loadData(error_html, WebString::fromUTF8("text/html"),
                    WebString::fromUTF8("UTF-8"), GURL(kUnreachableWebDataURL),
                    error.unreachableURL, replace, frame_load_type, history_item,
                    blink::WebHistoryDifferentDocumentLoad, false);
 }
 
 void RenderFrameImpl::DidMeaningfulLayout(
     blink::WebMeaningfulLayout layout_type) {
   for (auto& observer : observers_)
     observer.DidMeaningfulLayout(layout_type);
@@ skipping 4256 matching lines @@
   // event target. Potentially a Pepper plugin will receive the event.
   // In order to tell whether a plugin gets the last mouse event and which it
   // is, we set |pepper_last_mouse_event_target_| to null here. If a plugin gets
   // the event, it will notify us via DidReceiveMouseEvent() and set itself as
   // |pepper_last_mouse_event_target_|.
   pepper_last_mouse_event_target_ = nullptr;
 #endif
 }
 
 }  // namespace content