Bug 1648157 - Add getter for windowUtils.desktopModeViewport. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D93006

dom/base/nsDOMWindowUtils.cpp

@@ -2149,6 +2149,13 @@ nsDOMWindowUtils::IsInModalState(bool* retval) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMWindowUtils::GetDesktopModeViewport(bool* retval) {
+  nsCOMPtr<nsPIDOMWindowOuter> window = do_QueryReferent(mWindow);
+  *retval = window && window->IsDesktopModeViewport();
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDOMWindowUtils::SetDesktopModeViewport(bool aDesktopMode) {
   nsCOMPtr<nsPIDOMWindowOuter> window = do_QueryReferent(mWindow);

dom/interfaces/base/nsIDOMWindowUtils.idl

@@ -1323,9 +1323,9 @@ interface nsIDOMWindowUtils : nsISupports {
   boolean isInModalState();
 
   /**
-   * Request set internal desktopMode flag change.
+   * Internal desktopMode flag.
    */
-  void setDesktopModeViewport(in boolean aDesktopModeViewport);
+  attribute boolean desktopModeViewport;
 
   /**
    * Suspend/resume timeouts on this window and its descendant windows.