ThreadRestrictions: disallow blocking IO on the UI thread

chrome/browser/extensions/crx_installer.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/extensions/crx_installer.h"
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
 #include "base/singleton.h"
 #include "base/stringprintf.h"
 #include "base/task.h"
+#include "base/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/extensions/convert_user_script.h"
 #include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/extensions/extension_error_reporter.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/browser/web_applications/web_app.h"
@@ skipping 80 matching lines @@
 
   // Make sure the UI is deleted on the ui thread.
   BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, client_);
   client_ = NULL;
 }
 
 void CrxInstaller::InstallCrx(const FilePath& source_file) {
   source_file_ = source_file;
 
   FilePath user_data_temp_dir;
-  CHECK(PathService::Get(chrome::DIR_USER_DATA_TEMP, &user_data_temp_dir));
+  {
+    // We shouldn't be doing disk IO on the UI thread.
+    //   http://code.google.com/p/chromium/issues/detail?id=60634
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    CHECK(PathService::Get(chrome::DIR_USER_DATA_TEMP, &user_data_temp_dir));
+  }
 
   scoped_refptr<SandboxedExtensionUnpacker> unpacker(
       new SandboxedExtensionUnpacker(
           source_file,
           user_data_temp_dir,
           g_browser_process->resource_dispatcher_host(),
           this));
 
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
@@ skipping 273 matching lines @@
     client_->OnInstallSuccess(extension_.get());
 
   // Tell the frontend about the installation and hand off ownership of
   // extension_ to it.
   frontend_->OnExtensionInstalled(extension_.release(),
                                   allow_privilege_increase_);
 
   // We're done. We don't post any more tasks to ourselves so we are deleted
   // soon.
 }