Thread IO safety: file_util annotated, IO thread blocked from doing IO

chrome/browser/printing/print_dialog_cloud_uitest.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/printing/print_dialog_cloud.h"
 #include "chrome/browser/printing/print_dialog_cloud_internal.h"
 
 #include <functional>
 
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/singleton.h"
+#include "base/thread_restrictions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_list.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_url.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/in_process_browser_test.h"
 #include "chrome/test/ui_test_utils.h"
 #include "net/url_request/url_request_filter.h"
 #include "net/url_request/url_request_test_job.h"
 #include "net/url_request/url_request_unittest.h"
 
 namespace {
 
 class TestData {
  public:
   TestData() {}
 
-  char* GetTestData() {
+  const char* GetTestData() {
+    // Fetching this data blocks the IO thread, but we don't really care because
+    // this is a test.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+
     if (test_data_.empty()) {
       FilePath test_data_directory;
       PathService::Get(chrome::DIR_TEST_DATA, &test_data_directory);
       FilePath test_file =
           test_data_directory.AppendASCII("printing/cloud_print_uitest.html");
       file_util::ReadFileToString(test_file, &test_data_);
     }
-    return &test_data_[0];
+    return test_data_.c_str();
   }
  private:
   std::string test_data_;
 };
 
 // A simple test URLRequestJob. We don't care what it does, only that
 // whether it starts and finishes.
 class SimpleTestJob : public URLRequestTestJob {
  public:
   explicit SimpleTestJob(URLRequest* request)
@@ skipping 177 matching lines @@
 
   std::wstring window_print(L"window.print()");
   browser()->GetSelectedTabContents()->render_view_host()->
       ExecuteJavascriptInWebFrame(std::wstring(), window_print);
 
   ui_test_utils::RunMessageLoop();
 
   ASSERT_TRUE(Singleton<TestController>()->result());
 }
 #endif