Bug 1611505. Remove now-unnecessary null-checks. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D61007

--HG--
extra : moz-landing-system : lando

dom/bindings/nsScriptError.cpp

@@ -428,18 +428,15 @@ bool nsScriptErrorBase::ComputeIsFromPrivateWindow(
     nsGlobalWindowInner* aWindow) {
   // Never mark exceptions from chrome windows as having come from private
   // windows, since we always want them to be reported.
-  // winPrincipal needs to be null-checked - Bug 1601175
   nsIPrincipal* winPrincipal = aWindow->GetPrincipal();
-  return aWindow->IsPrivateBrowsing() &&
-         (!winPrincipal || !winPrincipal->IsSystemPrincipal());
+  return aWindow->IsPrivateBrowsing() && !winPrincipal->IsSystemPrincipal();
 }
 
 /* static */
 bool nsScriptErrorBase::ComputeIsFromChromeContext(
     nsGlobalWindowInner* aWindow) {
   nsIPrincipal* winPrincipal = aWindow->GetPrincipal();
-  // winPrincipal needs to be null-checked - Bug 1601175
-  return (winPrincipal && winPrincipal->IsSystemPrincipal());
+  return winPrincipal->IsSystemPrincipal();
 }
 
 NS_IMPL_ISUPPORTS(nsScriptError, nsIConsoleMessage, nsIScriptError)