[QR Generator] Disallow feature in Incognito.

Bug: 1072871
Change-Id: Id2dd5d796140df35110834c3ac66b9a7da45a15b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2158039Reviewed-by: Kristi Park <kristipark@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Commit-Queue: Travis Skare <skare@chromium.org>
Cr-Commit-Position: refs/heads/master@{#763395}

chrome/browser/renderer_context_menu/render_view_context_menu.cc

@@ -2662,6 +2662,9 @@ bool RenderViewContextMenu::IsQRCodeGeneratorEnabled() const {
   if (!base::FeatureList::IsEnabled(kSharingQRCodeGenerator))
     return false;
 
+  if (browser_context_->IsOffTheRecord())
+    return false;
+
   NavigationEntry* entry =
       embedder_web_contents_->GetController().GetLastCommittedEntry();
   if (!entry || !content::IsSavableURL(entry->GetURL()))