Revert 63600 - Thread IO safety: annotate file_util, and block IO thread from...

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
===================================================================
--- chrome/browser/io_thread.cc	(revision 63629)
+++ chrome/browser/io_thread.cc	(working copy)
@@ -12,7 +12,6 @@
 #include "base/string_number_conversions.h"
 #include "base/string_split.h"
 #include "base/string_util.h"
-#include "base/thread_restrictions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/gpu_process_host.h"
@@ -258,13 +257,6 @@
 }
 
 void IOThread::Init() {
-#if defined(OS_LINUX)
-  // TODO(evan): test and enable this on all platforms.
-  // Though this thread is called the "IO" thread, it actually just routes
-  // messages around; it shouldn't be allowed to perform any blocking disk I/O.
-  base::ThreadRestrictions::SetIOAllowed(false);
-#endif
-
   BrowserProcessSubThread::Init();
 
   DCHECK_EQ(MessageLoop::TYPE_IO, message_loop()->type());