Bug 1418752 - Firefox instahang on start after landing patch from bug #1392841.vr=honzab

Initialize in advance all security services whose initialization on background thread could cause a deadlock.

netwerk/base/nsNetUtil.cpp

@@ -75,6 +75,8 @@
 #include "nsHttpHandler.h"
 #include "nsNSSComponent.h"
 #include "nsIRedirectHistoryEntry.h"
+#include "nsICertBlocklist.h"
+#include "nsICertOverrideService.h"
 
 #include <limits>
 
@@ -2659,6 +2661,10 @@ void net_EnsurePSMInit()
     nsresult rv;
     nsCOMPtr<nsISupports> psm = do_GetService(PSM_COMPONENT_CONTRACTID, &rv);
     MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+    nsCOMPtr<nsISupports> sss = do_GetService(NS_SSSERVICE_CONTRACTID);
+    nsCOMPtr<nsISupports> cbl = do_GetService(NS_CERTBLOCKLIST_CONTRACTID);
+    nsCOMPtr<nsISupports> cos = do_GetService(NS_CERTOVERRIDE_CONTRACTID);
 }
 
 bool NS_IsAboutBlank(nsIURI *uri)

security/manager/ssl/nsNSSModule.cpp

@@ -162,6 +162,10 @@ NS_DEFINE_NAMED_CID(NS_SECURE_BROWSER_UI_CID);
 NS_DEFINE_NAMED_CID(NS_SITE_SECURITY_SERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_CERT_BLOCKLIST_CID);
 
+// Components that require main thread initialization could cause a deadlock
+// in necko code (bug 1418752). To prevent it we initialize all such components
+// on main thread in advance in net_EnsurePSMInit(). Update that function when
+// new component with ThreadRestriction::MainThreadOnly is added.
 static const mozilla::Module::CIDEntry kNSSCIDs[] = {
   { &kNS_NSSCOMPONENT_CID, false, nullptr, nsNSSComponentConstructor },
   { &kNS_SSLSOCKETPROVIDER_CID, false, nullptr,