Suppress a ThreadAssertion warning when joining worker thread for PAC scripts...

net/proxy/multi_threaded_proxy_resolver.cc

Index: net/proxy/multi_threaded_proxy_resolver.cc
===================================================================
--- net/proxy/multi_threaded_proxy_resolver.cc	(revision 71199)
+++ net/proxy/multi_threaded_proxy_resolver.cc	(working copy)
@@ -8,6 +8,7 @@
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread.h"
+#include "base/threading/thread_restrictions.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
 #include "net/proxy/proxy_info.h"
@@ -336,9 +337,14 @@
   // to avoid deadlocks.
   resolver_->Shutdown();
 
-  // Join the worker thread.
-  thread_.reset();
+  {
+    // See http://crbug.com/69710.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
 
+    // Join the worker thread.
+    thread_.reset();
+  }
+
   // Cancel any outstanding job.
   if (outstanding_job_) {
     outstanding_job_->Cancel();