Turn on file access checks on Win.

chrome/browser/dom_ui/shared_resources_data_source.cc

 // Copyright (c) 2010 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/dom_ui/shared_resources_data_source.h"
 
 #include "app/resource_bundle.h"
 #include "base/singleton.h"
+#include "base/thread_restrictions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/io_thread.h"
 #include "chrome/common/url_constants.h"
 #include "grit/generated_resources.h"
 #include "grit/shared_resources.h"
 #include "grit/shared_resources_map.h"
 #include "grit/app_resources.h"
 #include "grit/theme_resources.h"
@@ skipping 53 matching lines @@
                                                  int request_id) {
   int idr = PathToIDR(path);
   DCHECK_NE(-1, idr);
   const ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   scoped_refptr<RefCountedStaticMemory> bytes(rb.LoadDataResourceBytes(idr));
   SendResponse(request_id, bytes);
 }
 
 std::string SharedResourcesDataSource::GetMimeType(
     const std::string& path) const {
+  // Requests should not block on the disk!  On Windows this goes to the
+  // registry.
+  //   http://code.google.com/p/chromium/issues/detail?id=59849
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+
   std::string mime_type;
   net::GetMimeTypeFromFile(FilePath().AppendASCII(path), &mime_type);
   return mime_type;
 }