ThreadRestrictions: disallow blocking IO on the UI thread

chrome/browser/spellcheck_host.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/spellcheck_host.h"
 
 #include <fcntl.h>
 
 #include "app/l10n_util.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/string_split.h"
+#include "base/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/prefs/pref_member.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/spellcheck_host_observer.h"
 #include "chrome/browser/spellchecker_platform_engine.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/net/url_request_context_getter.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/spellcheck_common.h"
 #include "googleurl/src/gurl.h"
 
 namespace {
 
 FilePath GetFirstChoiceFilePath(const std::string& language) {
   FilePath dict_dir;
-  PathService::Get(chrome::DIR_APP_DICTIONARIES, &dict_dir);
+  {
+    // This should not do blocking IO from the UI thread!
+    // Temporarily allow it for now.
+    //   http://code.google.com/p/chromium/issues/detail?id=60643
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    PathService::Get(chrome::DIR_APP_DICTIONARIES, &dict_dir);
+  }
   return SpellCheckCommon::GetVersionedFileName(language, dict_dir);
 }
 
 #if defined(OS_WIN)
 FilePath GetFallbackFilePath(const FilePath& first_choice) {
   FilePath dict_dir;
   PathService::Get(chrome::DIR_USER_DATA, &dict_dir);
   return dict_dir.Append(first_choice.BaseName());
 }
 #endif
@@ skipping 260 matching lines @@
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
           NewRunnableMethod(this,
               &SpellCheckHost::InformObserverOfInitialization));
       return;
     }
   }
 
   data_.clear();
   Initialize();
 }