Adding instrumentation to locate the source of jankiness.

net/base/upload_file_element_reader.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/base/upload_file_element_reader.h"
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
+#include "base/profiler/scoped_profile.h"
 #include "base/task_runner_util.h"
 #include "net/base/file_stream.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 
 namespace net {
 
 namespace {
 
 // In tests, this value is used to override the return value of
@@ skipping 76 matching lines @@
 void UploadFileElementReader::Reset() {
   weak_ptr_factory_.InvalidateWeakPtrs();
   bytes_remaining_ = 0;
   content_length_ = 0;
   file_stream_.reset();
 }
 
 void UploadFileElementReader::OnOpenCompleted(
     const CompletionCallback& callback,
     int result) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 UploadFileElementReader::OnOpenCompleted"));
+
   DCHECK(!callback.is_null());
 
   if (result < 0) {
     DLOG(WARNING) << "Failed to open \"" << path_.value()
                   << "\" for reading: " << result;
     callback.Run(result);
     return;
   }
 
   if (range_offset_) {
@@ skipping 87 matching lines @@
 ScopedOverridingContentLengthForTests(uint64 value) {
   overriding_content_length = value;
 }
 
 UploadFileElementReader::ScopedOverridingContentLengthForTests::
 ~ScopedOverridingContentLengthForTests() {
   overriding_content_length = 0;
 }
 
 }  // namespace net