Bug 1476405: Part 5 - Create nsThread wrapper and use reasonable stack size for BackgroundHangMonitor. r=erahm

BackgroundHangMonitor is a special snowflake, and uses PR_CreateThread
directly, for some reason.

MozReview-Commit-ID: 2Qg28EqDwM7

--HG--
extra : source : b2a99f50e642cc3dc41ab540e7639d2c39bbe75b
extra : histedit_source : 603bd726eafdb53aaafd98337b41da1259464cc7

toolkit/components/backgroundhangmonitor/BackgroundHangMonitor.cpp

@@ -268,7 +268,8 @@ BackgroundHangManager::BackgroundHangManager()
 
   mHangMonitorThread = PR_CreateThread(
     PR_USER_THREAD, MonitorThread, this,
-    PR_PRIORITY_LOW, PR_GLOBAL_THREAD, PR_JOINABLE_THREAD, 0);
+    PR_PRIORITY_LOW, PR_GLOBAL_THREAD, PR_JOINABLE_THREAD,
+    nsIThreadManager::DEFAULT_STACK_SIZE);
 
   MOZ_ASSERT(mHangMonitorThread, "Failed to create BHR monitor thread");