Adding instrumentation to locate the source of jankiness.

net/url_request/url_request_simple_job.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/url_request/url_request_simple_job.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop/message_loop.h"
+#include "base/profiler/scoped_profile.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_util.h"
 #include "net/url_request/url_request_status.h"
 
 namespace net {
 
 URLRequestSimpleJob::URLRequestSimpleJob(
     URLRequest* request, NetworkDelegate* network_delegate)
@@ skipping 31 matching lines @@
   data_offset_ += buf_size;
   *bytes_read = buf_size;
   return true;
 }
 
 void URLRequestSimpleJob::StartAsync() {
   if (!request_)
     return;
 
   if (ranges().size() > 1) {
+    // TODO(vadimt): Remove ScopedProfile below once crbug.com/422489 is fixed.
+    tracked_objects::ScopedProfile tracking_profile(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "422489 URLRequestSimpleJob::StartAsync 1"));
+
     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
                                 ERR_REQUEST_RANGE_NOT_SATISFIABLE));
     return;
   }
 
   if (!ranges().empty() && range_parse_result() == OK)
     byte_range_ = ranges().front();
 
-  int result = GetData(&mime_type_, &charset_, &data_,
-                       base::Bind(&URLRequestSimpleJob::OnGetDataCompleted,
-                                  weak_factory_.GetWeakPtr()));
-  if (result != ERR_IO_PENDING)
+  int result;
+  {
+    // TODO(vadimt): Remove ScopedProfile below once crbug.com/422489 is fixed.
+    // Remove the block and assign 'result' in its declaration.
+    tracked_objects::ScopedProfile tracking_profile(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "422489 URLRequestSimpleJob::StartAsync 2"));
+
+    result = GetData(&mime_type_,
+                     &charset_,
+                     &data_,
+                     base::Bind(&URLRequestSimpleJob::OnGetDataCompleted,
+                                weak_factory_.GetWeakPtr()));
+  }
+
+  if (result != ERR_IO_PENDING) {
+    // TODO(vadimt): Remove ScopedProfile below once crbug.com/422489 is fixed.
+    tracked_objects::ScopedProfile tracking_profile(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "422489 URLRequestSimpleJob::StartAsync 3"));
+
     OnGetDataCompleted(result);
+  }
 }
 
 void URLRequestSimpleJob::OnGetDataCompleted(int result) {
   if (result == OK) {
     // Notify that the headers are complete
     if (!byte_range_.ComputeBounds(data_.size())) {
       NotifyDone(URLRequestStatus(URLRequestStatus::FAILED,
                  ERR_REQUEST_RANGE_NOT_SATISFIABLE));
       return;
     }
 
     data_offset_ = byte_range_.first_byte_position();
     int remaining_bytes = byte_range_.last_byte_position() -
         byte_range_.first_byte_position() + 1;
     set_expected_content_size(remaining_bytes);
     NotifyHeadersComplete();
   } else {
     NotifyStartError(URLRequestStatus(URLRequestStatus::FAILED, result));
   }
 }
 
 }  // namespace net