[NOT FOR LANDING] Detailed loading traces

extensions/browser/api/web_request/web_request_api.cc

Index: extensions/browser/api/web_request/web_request_api.cc
diff --git a/extensions/browser/api/web_request/web_request_api.cc b/extensions/browser/api/web_request/web_request_api.cc
index aa799bbe459cf3a32a24607a19e377baddbd6a46..cb4c54742824de592b98d9606dce8f8fd7807bd9 100644
--- a/extensions/browser/api/web_request/web_request_api.cc
+++ b/extensions/browser/api/web_request/web_request_api.cc
@@ -616,17 +616,23 @@ int ExtensionWebRequestEventRouter::OnBeforeRequest(
     net::URLRequest* request,
     const net::CompletionCallback& callback,
     GURL* new_url) {
+  TRACE_EVENT0("toplevel", "ExtensionWebRequestEventRouter::OnBeforeRequest");
+
   if (ShouldHideEvent(browser_context, extension_info_map, request))
     return net::OK;
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::A");
 
   if (IsPageLoad(request))
     NotifyPageLoad();
-
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::B");
   request_time_tracker_->LogRequestStartTime(request->identifier(),
                                              base::Time::Now(),
                                              request->url(),
                                              browser_context);
-
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::C");
   // Whether to initialized |blocked_requests_|.
   bool initialize_blocked_requests = false;
 
@@ -634,11 +640,14 @@ int ExtensionWebRequestEventRouter::OnBeforeRequest(
       ProcessDeclarativeRules(browser_context, extension_info_map,
                               web_request::OnBeforeRequest::kEventName, request,
                               ON_BEFORE_REQUEST, NULL);
-
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::D");
   int extra_info_spec = 0;
   EventListeners listeners = GetMatchingListeners(
       browser_context, extension_info_map,
       web_request::OnBeforeRequest::kEventName, request, &extra_info_spec);
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::E");
   if (!listeners.empty() &&
       !GetAndSetSignaled(request->identifier(), kOnBeforeRequest)) {
     scoped_ptr<WebRequestEventDetails> event_details(
@@ -648,7 +657,8 @@ int ExtensionWebRequestEventRouter::OnBeforeRequest(
     initialize_blocked_requests |= DispatchEvent(
         browser_context, request, listeners, std::move(event_details));
   }
-
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::F");
   if (!initialize_blocked_requests)
     return net::OK;  // Nobody saw a reason for modifying the request.
 
@@ -659,7 +669,8 @@ int ExtensionWebRequestEventRouter::OnBeforeRequest(
   blocked_request.callback = callback;
   blocked_request.new_url = new_url;
   blocked_request.net_log = &request->net_log();
-
+  TRACE_EVENT0("toplevel",
+               "ExtensionWebRequestEventRouter::OnBeforeRequest::G");
   if (blocked_request.num_handlers_blocking == 0) {
     // If there are no blocking handlers, only the declarative rules tried
     // to modify the request and we can respond synchronously.