Implement chrome.downloads.onDeterminingFilename()

chrome/browser/extensions/api/web_request/web_request_api.cc

Index: chrome/browser/extensions/api/web_request/web_request_api.cc
diff --git a/chrome/browser/extensions/api/web_request/web_request_api.cc b/chrome/browser/extensions/api/web_request/web_request_api.cc
index 7a09ec4b7ab5aab415b81499864d8ed3e55ba13a..24c9f526bc75e6c2262e738cbdd3122e4b88e8d7 100644
--- a/chrome/browser/extensions/api/web_request/web_request_api.cc
+++ b/chrome/browser/extensions/api/web_request/web_request_api.cc
@@ -369,6 +369,9 @@ void SendOnMessageEventOnUI(
 // Represents a single unique listener to an event, along with whatever filter
 // parameters and extra_info_spec were specified at the time the listener was
 // added.
+// NOTE(benjhayden) New APIs should not use this sub_event_name trick! It does
+// not play well with event pages. See downloads.onDeterminingFilename and
+// ExtensionDownloadsEventRouter for an alternative approach.
 struct ExtensionWebRequestEventRouter::EventListener {
   std::string extension_id;
   std::string extension_name;