Require a process ID when looking up RFHs by FrameTreeNode ID.

extensions/browser/extension_navigation_throttle.cc

 // Copyright 2016 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 "extensions/browser/extension_navigation_throttle.h"
 
 #include "components/guest_view/browser/guest_view_base.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
@@ skipping 90 matching lines @@
   // should always be allowed.
 
   // If the navigation is not to a chrome-extension:// URL, no need to perform
   // any more checks.
   if (!url.SchemeIs(extensions::kExtensionScheme))
     return content::NavigationThrottle::PROCEED;
 
   // The subframe which is navigated needs to have all of its ancestors be
   // at the same origin, otherwise the resource needs to be explicitly listed
   // in web_accessible_resources.
-  // Since the RenderFrameHost is not known until navigation has committed,
-  // we can't get it from NavigationHandle. However, this code only cares about
-  // the ancestor chain, so find the current RenderFrameHost and use it to
-  // traverse up to the main frame.
-  content::RenderFrameHost* navigating_frame =
-      web_contents->FindFrameByFrameTreeNodeId(
-          navigation_handle()->GetFrameTreeNodeId());
-  DCHECK(navigating_frame);
-
-  // Traverse the chain of parent frames, checking if they are the same origin
-  // as the URL of this navigation.
-  content::RenderFrameHost* ancestor = navigating_frame->GetParent();
+  content::RenderFrameHost* ancestor = navigation_handle()->GetParentFrame();

[Charlie Reis, 2017/05/04 16:29:58]

ekaramad/lazyboy: I'm further simplifying your recent refactor from
https://codereview.chromium.org/2858143002, now that we can just grab the parent
RFH directly.  (Otherwise, the FindFrameByFrameTreeNodeId call is a bit risky in
general, in case people tried to use navigating_frame in other ways.)

[EhsanK, 2017/05/04 18:01:38]

Thanks! This is quite useful in my current works so looking forward to a quick
rebase asap. Also I guess it should be more efficient given that we do not check
all frames for a matching ID.

   bool external_ancestor = false;
   while (ancestor) {
     if (ancestor->GetLastCommittedURL().GetOrigin() != url.GetOrigin()) {
       // Ignore DevTools, as it is allowed to embed extension pages.
       if (!ancestor->GetLastCommittedURL().SchemeIs(
               content::kChromeDevToolsScheme)) {
         external_ancestor = true;
         break;
       }
     }
@@ skipping 20 matching lines @@
   }
 
   return content::NavigationThrottle::BLOCK_REQUEST;
 }
 
 const char* ExtensionNavigationThrottle::GetNameForLogging() {
   return "ExtensionNavigationThrottle";
 }
 
 }  // namespace extensions