[NOT FOR LANDING] Detailed loading traces

content/browser/loader/throttling_resource_handler.cc

Index: content/browser/loader/throttling_resource_handler.cc
diff --git a/content/browser/loader/throttling_resource_handler.cc b/content/browser/loader/throttling_resource_handler.cc
index 93b9ad74836b88f74ffe3cf54a3b7c0789ab0f20..676cad7a4a40b32970d763abfb0a9dd92e69866b 100644
--- a/content/browser/loader/throttling_resource_handler.cc
+++ b/content/browser/loader/throttling_resource_handler.cc
@@ -5,6 +5,7 @@
 #include "content/browser/loader/throttling_resource_handler.h"
 
 #include <utility>
+#include "base/trace_event/trace_event.h"
 
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/public/browser/resource_throttle.h"
@@ -31,6 +32,8 @@ ThrottlingResourceHandler::ThrottlingResourceHandler(
 }
 
 ThrottlingResourceHandler::~ThrottlingResourceHandler() {
+  TRACE_EVENT0("toplevel",
+               "ThrottlingResourceHandler::~ThrottlingResourceHandler");
 }
 
 bool ThrottlingResourceHandler::OnRequestRedirected(
@@ -61,17 +64,24 @@ bool ThrottlingResourceHandler::OnRequestRedirected(
 }
 
 bool ThrottlingResourceHandler::OnWillStart(const GURL& url, bool* defer) {
+  TRACE_EVENT0("toplevel", "ThrottlingResourceHandler::OnWillStart");
   DCHECK(!cancelled_by_resource_throttle_);
 
   *defer = false;
   while (next_index_ < throttles_.size()) {
     int index = next_index_;
-    throttles_[index]->WillStartRequest(defer);
+    {
+      TRACE_EVENT0("toplevel", "Throttle::OnWillStartRequest");
+      throttles_[index]->WillStartRequest(defer);
+    }
     next_index_++;
     if (cancelled_by_resource_throttle_)
       return false;
     if (*defer) {
-      OnRequestDefered(index);
+      {
+        TRACE_EVENT0("toplevel", "ThrottlingResourceHandler::OnRequestDefered");
+        OnRequestDefered(index);
+      }
       deferred_stage_ = DEFERRED_START;
       deferred_url_ = url;
       return true;  // Do not cancel.
@@ -109,6 +119,8 @@ bool ThrottlingResourceHandler::OnBeforeNetworkStart(const GURL& url,
 
 bool ThrottlingResourceHandler::OnResponseStarted(ResourceResponse* response,
                                                   bool* defer) {
+  TRACE_EVENT0("toplevel", "ThrottlingResourceHandler::OnResponseStarted");
+
   DCHECK(!cancelled_by_resource_throttle_);
 
   while (next_index_ < throttles_.size()) {