Bug 1449756 - Make DisplayPort suppression PresShell specific and not process global. r=kats

Originally, DisplayPort suppression was a process-global static. This change makes it possible
to control DisplayPort suppression on a per-PresShell basis.

Differential Revision: https://phabricator.services.mozilla.com/D1759

dom/base/nsDOMWindowUtils.cpp

@@ -4178,7 +4178,7 @@ NS_IMETHODIMP
 nsDOMWindowUtils::RespectDisplayPortSuppression(bool aEnabled)
 {
   nsCOMPtr<nsIPresShell> shell(GetPresShell());
-  APZCCallbackHelper::RespectDisplayPortSuppression(aEnabled, shell);
+  shell->RespectDisplayportSuppression(aEnabled);
   return NS_OK;
 }