[Extensions] Expand capabilities to about:blank iframes within a page

extensions/renderer/dispatcher.cc

 // Copyright 2014 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/renderer/dispatcher.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 1431 matching lines @@
     if (info && info->matches.MatchesURL(context->url()))
       return true;
   }
   return false;
 }
 
 void Dispatcher::UpdateContentCapabilities(ScriptContext* context) {
   APIPermissionSet permissions;
   for (const auto& extension :
        *RendererExtensionRegistry::Get()->GetMainThreadExtensionSet()) {
+    blink::WebLocalFrame* web_frame = context->web_frame();
+    GURL url = context->url();
+    // We allow about:blank pages to take on the privileges of their parents if
+    // they aren't sandboxed.
+    if (web_frame && !web_frame->getSecurityOrigin().isUnique())
+      url = ScriptContext::GetEffectiveDocumentURL(web_frame, url, true);
     const ContentCapabilitiesInfo& info =
         ContentCapabilitiesInfo::Get(extension.get());
-    if (info.url_patterns.MatchesURL(context->url())) {
+    if (info.url_patterns.MatchesURL(url)) {
       APIPermissionSet new_permissions;
       APIPermissionSet::Union(permissions, info.permissions, &new_permissions);
       permissions = new_permissions;
     }
   }
   context->set_content_capabilities(permissions);
 }
 
 void Dispatcher::PopulateSourceMap() {
   const std::vector<std::pair<std::string, int> > resources = GetJsResources();
@@ skipping 137 matching lines @@
   // The "guestViewDeny" module must always be loaded last. It registers
   // error-providing custom elements for the GuestView types that are not
   // available, and thus all of those types must have been checked and loaded
   // (or not loaded) beforehand.
   if (context_type == Feature::BLESSED_EXTENSION_CONTEXT) {
     module_system->Require("guestViewDeny");
   }
 }
 
 }  // namespace extensions