When allowing an extension file:/// URL access, grant its process access to that scheme.

chrome/browser/renderer_host/chrome_render_view_host_observer.cc

 // Copyright (c) 2011 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 "chrome/browser/renderer_host/chrome_render_view_host_observer.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/dom_operation_notification_details.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/net/predictor.h"
@@ skipping 98 matching lines @@
   }
 
   // Some extensions use chrome:// URLs.
   Extension::Type type = extension->GetType();
   if (type == Extension::TYPE_EXTENSION ||
       type == Extension::TYPE_PACKAGED_APP) {
     ChildProcessSecurityPolicy::GetInstance()->GrantScheme(
         process->id(), chrome::kChromeUIScheme);
   }
 
+  if (type == Extension::TYPE_EXTENSION &&
+      profile_->GetExtensionService()->extension_prefs()->AllowFileAccess(
+          extension->id())) {
+    ChildProcessSecurityPolicy::GetInstance()->GrantScheme(
+        process->id(), chrome::kFileScheme);
+  }
+
   if (type == Extension::TYPE_EXTENSION ||
       type == Extension::TYPE_USER_SCRIPT ||
       type == Extension::TYPE_PACKAGED_APP ||
       (type == Extension::TYPE_HOSTED_APP &&
        extension->location() == Extension::COMPONENT)) {
     Send(new ExtensionMsg_ActivateExtension(extension->id()));
   }
 }
 
 const Extension* ChromeRenderViewHostObserver::GetExtension() {
@@ skipping 38 matching lines @@
       content::Source<RenderViewHost>(render_view_host()),
       content::Details<DomOperationNotificationDetails>(&details));
 }
 
 void ChromeRenderViewHostObserver::OnFocusedEditableNodeTouched() {
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_FOCUSED_EDITABLE_NODE_TOUCHED,
       content::Source<RenderViewHost>(render_view_host()),
       content::NotificationService::NoDetails());
 }