Adding instrumentation to locate the source of jankiness.

content/browser/fileapi/mock_url_request_delegate.cc

 // Copyright 2014 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 "mock_url_request_delegate.h"
 
+#include "base/profiler/scoped_tracker.h"
 #include "base/run_loop.h"
 #include "net/base/io_buffer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 const int kBufferSize = 1024;
 }
 
 namespace content {
 
 MockURLRequestDelegate::MockURLRequestDelegate()
     : io_buffer_(new net::IOBuffer(kBufferSize)) {
 }
 
 MockURLRequestDelegate::~MockURLRequestDelegate() {
 }
 
 void MockURLRequestDelegate::OnResponseStarted(net::URLRequest* request) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/422516 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422516 MockURLRequestDelegate::OnResponseStarted"));
+
   if (request->status().is_success()) {
     EXPECT_TRUE(request->response_headers());
     ReadSome(request);
   } else {
     RequestComplete();
   }
 }
 
 void MockURLRequestDelegate::OnReadCompleted(net::URLRequest* request,
                                              int bytes_read) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/422516 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422516 MockURLRequestDelegate::OnReadCompleted"));
+
   if (bytes_read > 0)
     ReceiveData(request, bytes_read);
   else
     RequestComplete();
 }
 
 void MockURLRequestDelegate::ReadSome(net::URLRequest* request) {
   if (!request->is_pending()) {
     RequestComplete();
     return;
@@ skipping 18 matching lines @@
   } else {
     RequestComplete();
   }
 }
 
 void MockURLRequestDelegate::RequestComplete() {
   base::MessageLoop::current()->Quit();
 }
 
 }  // namespace