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

content/browser/frame_host/navigation_handle_impl.cc

 // 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.
 
 #include "content/browser/frame_host/navigation_handle_impl.h"
 
 #include <utility>
 
+#include "content/browser/frame_host/ancestor_throttle.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/navigator.h"
 #include "content/browser/frame_host/navigator_delegate.h"
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
 #include "content/browser/service_worker/service_worker_navigation_handle.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/content_client.h"
 #include "net/url_request/redirect_info.h"
 
@@ skipping 207 matching lines @@
   // Update the navigation parameters.
   is_post_ = is_post;
   sanitized_referrer_ = sanitized_referrer;
   has_user_gesture_ = has_user_gesture;
   transition_ = transition;
   is_external_protocol_ = is_external_protocol;
 
   state_ = WILL_SEND_REQUEST;
   complete_callback_ = callback;
 
-  // Register the navigation throttles. The ScopedVector returned by
-  // GetNavigationThrottles is not assigned to throttles_ directly because it
-  // would overwrite any throttle previously added with
-  // RegisterThrottleForTesting.
+  // Register the platform's navigation throttles.
+  scoped_ptr<content::NavigationThrottle> ancestor_throttle =
+      AncestorThrottle::MaybeCreateThrottleFor(this);
+  if (ancestor_throttle)
+    throttles_.push_back(std::move(ancestor_throttle));
+
+  // Register the embedder's navigation throttles.
   ScopedVector<NavigationThrottle> throttles_to_register =
       GetContentClient()->browser()->CreateThrottlesForNavigation(this);
   if (throttles_to_register.size() > 0) {
     throttles_.insert(throttles_.end(), throttles_to_register.begin(),
                       throttles_to_register.end());
     throttles_to_register.weak_clear();
   }
 
   // Notify each throttle of the request.
   NavigationThrottle::ThrottleCheckResult result = CheckWillStartRequest();
@@ skipping 86 matching lines @@
       case NavigationThrottle::CANCEL:
       case NavigationThrottle::CANCEL_AND_IGNORE:
         state_ = CANCELING;
         return result;
 
       case NavigationThrottle::DEFER:
         state_ = DEFERRING_START;
         next_index_ = i + 1;
         return result;
 
-      default:
+      case NavigationThrottle::BLOCK_RESPONSE:

[nasko, 2016/02/12 23:21:40]

Why did we lose the default?

[Mike West, 2016/04/12 20:13:30]

Because this completely enumerates all the options of
`NavigationThrottle::ThrottleCheckResult`, so the `default:` will never be hit,
and the compiler will tell us when we need to add a new item?

         NOTREACHED();
     }
   }
   next_index_ = 0;
   state_ = WILL_SEND_REQUEST;
   return NavigationThrottle::PROCEED;
 }
 
 NavigationThrottle::ThrottleCheckResult
 NavigationHandleImpl::CheckWillRedirectRequest() {
@@ skipping 10 matching lines @@
       case NavigationThrottle::CANCEL:
       case NavigationThrottle::CANCEL_AND_IGNORE:
         state_ = CANCELING;
         return result;
 
       case NavigationThrottle::DEFER:
         state_ = DEFERRING_REDIRECT;
         next_index_ = i + 1;
         return result;
 
-      default:
+      case NavigationThrottle::BLOCK_RESPONSE:
         NOTREACHED();
     }
   }
   next_index_ = 0;
   state_ = WILL_REDIRECT_REQUEST;
   return NavigationThrottle::PROCEED;
 }
 
 NavigationThrottle::ThrottleCheckResult
 NavigationHandleImpl::CheckWillProcessResponse() {
   DCHECK(state_ == WILL_PROCESS_RESPONSE && next_index_ == 0);
   for (size_t i = next_index_; i < throttles_.size(); ++i) {
     NavigationThrottle::ThrottleCheckResult result =
         throttles_[i]->WillProcessResponse();
     switch (result) {
       case NavigationThrottle::PROCEED:
         continue;
 
+      case NavigationThrottle::BLOCK_RESPONSE:
       case NavigationThrottle::CANCEL:
       case NavigationThrottle::CANCEL_AND_IGNORE:
         state_ = CANCELING;
         return result;
 
       case NavigationThrottle::DEFER:
         NOTREACHED();
     }
   }
   state_ = WILL_PROCESS_RESPONSE;
   return NavigationThrottle::PROCEED;
 }
 
 void NavigationHandleImpl::RunCompleteCallback(
     NavigationThrottle::ThrottleCheckResult result) {
   DCHECK(result != NavigationThrottle::DEFER);
 
   if (!complete_callback_.is_null()) {
     ThrottleChecksFinishedCallback callback = std::move(complete_callback_);
     callback.Run(result);
   }
 
   // No code after running the calback, as it might result in our destruction.
 }
 
 }  // namespace content