Make WebUI webview content script work with incognito.

extensions/browser/guest_view/web_view/web_view_content_script_manager.cc

Index: extensions/browser/guest_view/web_view/web_view_content_script_manager.cc
diff --git a/extensions/browser/guest_view/web_view/web_view_content_script_manager.cc b/extensions/browser/guest_view/web_view/web_view_content_script_manager.cc
index 15ede19ff331f09e80ce3c4bd568ea9fcfbe411b..7a3383dff703fe2d450b998d8cfbbd8c114cddc0 100644
--- a/extensions/browser/guest_view/web_view/web_view_content_script_manager.cc
+++ b/extensions/browser/guest_view/web_view/web_view_content_script_manager.cc
@@ -122,6 +122,8 @@ void WebViewContentScriptManager::AddContentScripts(
           ->GetDeclarativeUserScriptMasterByID(host_id);
   DCHECK(master);
 
+  bool is_incognito = browser_context_->IsOffTheRecord();
+
   // We need to update WebViewRenderState in the IO thread if the guest exists.
   std::set<int> ids_to_add;
 
@@ -154,7 +156,8 @@ void WebViewContentScriptManager::AddContentScripts(
   }
 
   // Step 3: adds new scripts to the master.
-  master->AddScripts(scripts, embedder_process_id, embedder_routing_id);
+  master->AddScripts(
+      scripts, embedder_process_id, embedder_routing_id, is_incognito);
 
   // Step 4: creates owner web contents observer for the given
   // |embedder_web_contents| if it doesn't exist.