Bug 1652318. Freeze docshell tree navigation at the same time for bot…

…h print and print preview. r=bobowen

I specifically want to move this to happen before the static clone is made, in
preparation for splitting out the static clone logic from DoCommonPrint.

Differential Revision: https://phabricator.services.mozilla.com/D83260

layout/printing/nsPrintJob.cpp

@@ -578,8 +578,16 @@ nsresult nsPrintJob::DoCommonPrint(bool aIsPrintPreview,
     nsCOMPtr<nsIPrintingPromptService> pps(
         do_QueryInterface(aWebProgressListener));
     mProgressDialogIsShown = pps != nullptr;
+
+    mIsCreatingPrintPreview = true;
+
+    // ensures docShell tree navigation in frozen
+    SetIsPrintPreview(true);
   } else {
     mProgressDialogIsShown = false;
+
+    // ensures docShell tree navigation in frozen
+    SetIsPrinting(true);
   }
 
   // Grab the new instance with local variable to guarantee that it won't be
@@ -606,9 +614,6 @@ nsresult nsPrintJob::DoCommonPrint(bool aIsPrintPreview,
     // to mPrtPreview once we've finish creating the print preview. We must
     // clear mPtrPreview so that code will use mPtr until that happens.
     mPrtPreview = nullptr;
-
-    mIsCreatingPrintPreview = true;
-    SetIsPrintPreview(true);
   }
 
   // Create a print session and let the print settings know about it.
@@ -687,10 +692,6 @@ nsresult nsPrintJob::DoCommonPrint(bool aIsPrintPreview,
     return NS_ERROR_FAILURE;
   }
 
-  if (!aIsPrintPreview) {
-    SetIsPrinting(true);
-  }
-
   // XXX This isn't really correct...
   if (!printData->mPrintObject->mDocument ||
       !printData->mPrintObject->mDocument->GetRootElement())