ThreadRestrictions: disallow blocking IO on the UI thread

chrome/browser/browser_main.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/browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
 #include "app/hi_res_timer_manager.h"
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "app/system_monitor.h"
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/platform_thread.h"
 #include "base/process_util.h"
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
+#include "base/thread_restrictions.h"
 #include "base/time.h"
 #include "base/trace_event.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/browser_main_win.h"
 #include "chrome/browser/browser_init.h"
 #include "chrome/browser/prefs/browser_prefs.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 431 matching lines @@
   // and 1 if it can't be. This is for validation that the library is installed
   // and versioned properly for Chrome to find.
   if (command_line.HasSwitch(switches::kTestLoadLibcros))
     exit(!chromeos::CrosLibrary::Get()->EnsureLoaded());
 #endif
 }
 
 void RunUIMessageLoop(BrowserProcess* browser_process) {
   TRACE_EVENT_BEGIN("BrowserMain:MESSAGE_LOOP", 0, "");
 
+#if defined(OS_LINUX)
+  // If the UI thread blocks, the whole UI is unresponsive.
+  // Do not allow disk IO from the UI thread.
+  // TODO(evanm): turn this on for all platforms.
+  //   http://code.google.com/p/chromium/issues/detail?id=60211
+  base::ThreadRestrictions::SetIOAllowed(false);
+#endif
+
 #if defined(TOOLKIT_VIEWS)
   views::AcceleratorHandler accelerator_handler;
   MessageLoopForUI::current()->Run(&accelerator_handler);
 #elif defined(USE_X11)
   MessageLoopForUI::current()->Run(NULL);
 #elif defined(OS_POSIX)
   MessageLoopForUI::current()->Run();
 #endif
 
   TRACE_EVENT_END("BrowserMain:MESSAGE_LOOP", 0, "");
@@ skipping 1068 matching lines @@
   metrics->Stop();
 
   // browser_shutdown takes care of deleting browser_process, so we need to
   // release it.
   ignore_result(browser_process.release());
   browser_shutdown::Shutdown();
 
   TRACE_EVENT_END("BrowserMain", 0, 0);
   return result_code;
 }